Soil Improvement

Buku Penyelidikan Tanah untuk Perkerasan Jalan disusun untuk memberikan pemahaman praktis mengenai peran tanah sebagai dasar utama pembangunan jalan. Di dalamnya, pembaca akan diperkenalkan pada dasar-dasar perencanaan jalan, pentingnya survei pendahuluan, serta teknik penyelidikan geoteknik yang menjadi landasan dalam menentukan kualitas dan kekuatan perkerasan.

Pembahasan dilengkapi dengan uraian berbagai metode uji, seperti pengujian kadar air, berat isi, berat jenis, analisis saringan, hidrometer, batas-batas Atterberg, permeabilitas, proctor, hingga California Bearing Ratio (CBR). Selain itu, disajikan pula pengujian lapangan seperti Sand Cone dan Dynamic Cone Penetration (DCP) yang umum digunakan dalam dunia konstruksi.

Dengan penjelasan langkah demi langkah, contoh perhitungan, serta interpretasi hasil uji, buku ini hadir tidak hanya sebagai rujukan teknis bagi mahasiswa dan praktisi teknik sipil, tetapi juga sebagai bacaan yang mudah dipahami oleh masyarakat umum yang tertarik mengenal proses pembangunan jalan.

Melalui penyajian yang sederhana dan sistematis, buku ini diharapkan dapat menjadi bekal pengetahuan sekaligus inspirasi untuk mewujudkan infrastruktur jalan yang lebih kuat, aman, dan berkelanjutan di Indonesia.

The compaction and unconfined compressive strength (UCS) properties of soil-quarry dust mixtures were investigated at different compaction energies for 10 different soil samples of low to medium plasticity. The quarry dust content of the soil was varied from 0 – 40% by weight of the soil, and the soil-mixtures were subjected to Atterberg limit tests, compaction tests, and UCS tests. The results show that plasticity properties were reduced with increasing quarry dust content, while maximum dry unit weight (MDUW) increased with both quarry dust content and compaction energy. The optimum moisture content (OMC) was generally reduced with increasing quarry dust content, but the trend varied with different samples. The UCS values showed no clear trend in the samples studied, and the result suggested that addition of quarry dust does not necessarily increase the UCS of all soil samples but can lead to loss of strength in some soils. Several statistical and machine learning equations were developed for the prediction of MDUW, OMC, and UCS for soil-quarry dust mixtures using artificial neural network (ANN) and multiple linear regression analysis (MLRA). Using the coefficient of determination (R2) as a basis, it was observed that ANN made better predictions than MLRA.

Expansive soils are one of those kinds of soils whose volume change takes place while it comes in contact with water. Therefore, prior to construction of a road on such sub-grade, it is important either to remove the existing soil and replace it with a non-expansive soil or to improve the engineering properties of the existing soil by stabilization using additives which are sourced locally. The black cotton (expansive) soil was obtained from a borrow pit on the basement complex at Igbo-Ora in Oyo State, SouthWestern Nigeria. The borrow site lies within the coordinates Longitude 7⁰24'45" and latitude 3⁰18'34". The black cotton soils used in the study were collected from depths between 0.3-1.0m below ground level. The eggshell wastes were taken from Obasanjo Farms, Ota, Ogun State, Nigeria. The eggshells were milled into powder and then substituted for black cotton soil from 0% to 30% at 10% intervals while 0% eggshell powder substitution served as control experiment. In line with BS 1377 (1990) and other relevant codes, consistency tests were conducted on the composite materials of black cotton (on basement complex) mixed with varying degrees of eggshell powder for the determination of liquid limit, plastic limit, shrinkage limit, etc. It is evidently clear from the results that the percentage shrinkage limit became constant at 30% eggshell powder substitution in black cotton soil on basement complex which is an indication of constancy of volume.

Tanah lempung ekspansif merupakan salah satu jenis tanah yang sering menimbulkan masalah dalam konstruksi jalan. Sifatnya yang mudah mengembang ketika basah dan menyusut saat kering membuat lapisan tanah dasar (subgrade) tidak stabil, sehingga berpengaruh pada ketahanan perkerasan jalan. Kondisi ini menuntut adanya solusi yang tidak hanya efektif dari sisi teknis, tetapi juga ramah lingkungan dan berkelanjutan.

Buku ini membahas pemanfaatan limbah beton sebagai bahan stabilisasi tanah lempung ekspansif. Penulis menguraikan teori dasar dan metode yang menunjukkan bahwa limbah beton mampu meningkatkan kualitas tanah dasar untuk mendukung konstruksi perkerasan jalan.

Hadirnya buku ini diharapkan dapat menjadi referensi bagi mahasiswa, praktisi, maupun pihak-pihak yang membutuhkan. Selain memperkaya wawasan tentang rekayasa tanah, buku ini juga mendorong penerapan teknologi berkelanjutan yang mampu menjawab tantangan pembangunan infrastruktur sekaligus menjaga kelestarian lingkungan.

In this study, the effects of a road subgrade stabilized using black carbon on the rigid road pavement
thickness and cost were investigated. For this purpose, pure soil was subjected to sieve analysis, hydrometer,
consistency limits and pycnometer tests to determine its engineering properties. Afterwards, stabilized mixture
samples were prepared by adding black carbon in five different ratios (2.5, 5, 10, 15 and 20%) to the soil. Pure
and stabilized samples were subjected to the standard proctor test, maximum dry unit weights and optimum
water contents were determined. Mixture samples prepared were subjected to unconfined compression and CBR
tests after 28 days of curing period. Rigid road pavement thickness and cost were analyzed according to the
AASHTO method using the data obtained. According to the test results, it was observed that the highest
compressive strength was obtained from the mixture with 10% black carbon and the CBR value of the mixture
at this ratio increased by 2.87 times compared to the pure soil. As a result, thanks to the soil stabilization using
10% black carbon, it was determined that the pavement thickness reduced by 3 cm and the rigid pavement cost
by 9.68%.

In this study, the effects of improving a clayey soil with glass powder (GP) obtained from recycled waste
glass on the flexible pavement designed over it were investigated, focusing on layer thickness and first
construction costs. For this purpose, firstly, some tests were conducted to determine the properties of the soil
samples. Subsequently, proctor tests were performed on specimens prepared by adding 3%, 6%, 9%, 12%
GP by weight to the soil. Then, unconfined compression tests were performed on the prepared samples after
a curing period of 28 days. The results of the unconfined compression tests showed that the highest strength
was obtained from mixtures containing 9% GP. Lastly, following 28 days of curing, California bearing ratio
(CBR) tests were conducted on both untreated and 9% GP treated samples, revealing that the CBR value
increased by 142.7% with the addition of 9% GP. Based on the obtained CBR values, flexible pavement
designs were made on both improved and unimproved soils, and the layer thicknesses and costs were
investigated. The calculations indicated that the improvement with 9% GP reduced the pavement layer
thicknesses reduced and the costs by 1.3 %.

Abstract: In this study, the effects of subgrade soil improved by the usage of metakaolin on the layer thickness and construction cost of
a rigid road designed on it were investigated. First, soil classification tests were conducted to determine the soil class, and several
laboratory tests were performed to identify soil properties. Then, standard proctor tests were applied to soil samples prepared by
adding 3%, 6%, 9%, 12%, and 15% metakaolin by weight. Subsequently, unconfined compressive strength tests were conducted on the
samples prepared with different proportions of metakaolin after a curing period of 28 days. As a result of the tests, the highest strength
was obtained in samples containing 12% metakaolin. Then, after 28 days of curing, the California bearing ratio test was applied to the
samples prepared without additives and with 12% metakaolin, resulting in a 227.56% increase in strength value. After the
experimental studies, pavement layer thickness and cost were investigated according to the rigid pavement design guidelines
recommended by the American Association of State Highways and Transportation (AASHTO). As a result of the calculations, it was
determined that the subgrade improved with 12% metakaolin reduced the rigid pavement layer thickness by 29.17% and the cost by
2.68%.

The construction industry is increasingly pressured to adopt sustainable practices that reduce environmental impact while ensuring structural integrity. This study investigates the comparative performance and sustainability of micropiles constructed with fly ash-enhanced grout mixtures (MFA) and conventional micropiles (MC). Fly ash, an industrial by-product is incorporated into the grout mixture to improve sustainability and enhance soil-structural stability. Comprehensive site investigations and numerical simulations were conducted to evaluate critical performance metrics, including Factor of Safety (FoS), deformation, settlement, and strain distribution, during pre-and post-construction phases. The results demonstrate that MFA systems exhibit superior performance, characterized by a higher FoS reaching ~3.0, reduced deformation (less than 3.0 m), and minimized settlement (maximum of-4.2 m compared to-14.6 m in MC). These findings indicate that MFA delivers structural benefits and contributes to sustainability by utilizing waste materials. The study underscores the potential of MFA as a viable alternative to traditional micropile systems, offering significant environmental and performance advantages. Further research is recommended to assess MFA systems' long-term performance and scalability in diverse geotechnical applications.

La zone d'étude se situe à 20°50 de latitude Nord et 104°38 de longitude Est. Elle présente un climat subtropical d'altitude. La pluviométrie moyenne est de l'ordre de 1 500 mm avec des précipitations concentrées d'avril à octobre. La pluviométrie dont les variations régionales peuvent être fortes en zones de relief avec des régimes mono-modaux classiques de mousson du type de la Figure Dans la Province de Son La le total pluviométrique ne dépasse pas 1.400 mm, avec des pluies étalées entre avril et octobre. Il existe donc une longue saison sèche de 5 mois et des risques d'épisodes secs au sein de la saison des pluies notamment en début.

This paper shows the results of an experimental study conducted to research the impact of waste marble powder (WMP) and fly ash (FA) on the fluidity (marsh cone flow time (MCFT), mini-slump diameter and plate cohesion meter (PCM)) and the rheological properties (viscosity and yield stress) of cement based grout (CBG) mixtures. The experiments were applied with the CBG mix including 1.00 water-binder (w/b) ratios and combined use of WMP (5-25%), FA (5-25%) and WMP+FA (10-30% + constant 25%). Test results illustrated that the rheological properties of the CBGs importantly have been improved by the addition of WMP, FA and WMP+FA to grout mix at w/b=1 ratio. Strongly shear thickening behaviour was got from the CBG mixtures the all WMP, FA and WMP+FA content. The increase in the percentage of WMP (5-25%) amount reduced the mini-slump flow diameter. Moreover, the increment in the percentage of FA (5-25%) amount increments the mini slum flow. According to the control sample, the increment in the percentage of WMP (10-25%) amount increased the mini-slump flow diameter for constant FA (25%) content. Also, the increase in WMP amount in the CBG mix, there is no effect on MCFT. Also, MCFT decreased with the increase of FA amount. Especially, FA increased the fluidity of CBG, when the WMP showed negative effect in increase the MCFT in WMP+FA content.

The evaluation of axial capacity of jet grouted soil cement columns in soft soil is a complicated issue because it depends according to the number of factors such as, soil type, influence mixture between soil and grouting materials, nozzle jet energy, jet grouting and water flow rate, rotation and lifting speed. These parameters related to the type of jet grouting methods (single, double and triple system). Most methods of design the bearing capacity of the jet-grouting column based on experience. Therefore, some designer calculates the bearing capacity of the jet grouting column based on jet grout section capacity. In this paper, different theoretical methods have been used to estimate of the jet grouting soil-cement capacity, such as Poulos and Davis, 1980 methods and then their comparison with the pile load test calculations based on the quick pile load test as presented in ASTM-D1143-07. Therefore, the study describes a prototype test single and group jet grout soil-cement models of arrangement (1 1, 1 2 and 2×2) for total length to diameter ratios (L/D) is 13.33 and clear spacing three times of diameter has been constructed in soft clayey soils in the right bank of the Euphrates River, at Al-Nasiriyah city. As a result, the theoretical method for estimation the bearing capacity gives unfaithful values for the single and group jet grout column compared to the load-settlement calculations obtained from field pile load test data. On the other hand, the Hansen's 90% and Butler and Hoy's given closer results to each other and may be considered faithful interpretation methods to compute the bearing capacity of single and group jet grouting columns.

The application areas of Mechanically Stabilized Earth (MSE) walls have also a large place in our country and in the world. It is also of great importance to determine dynamic loads that will affect the MSE walls, since MSE walls exhibit different behavior in terms of displacement, acceleration response and earth pressure from classical retaining structures under seismic loads. Equations for determining dynamic loads, displacements and acceleration responses acting on MSE walls are still lacking in the literature. Additionally, there are important deficiencies in the design codes and literature on the dynamic behavior of MSE wall system with discrete panels and polymeric geostrip which have been increasing in recent years. In this study, the seismic performances of MSE walls reinforced with polymeric geostrip reinforcement were investigated under sinusoidal acceleration excitations using a series of shaking table test. The effect of peak ground acceleration, stiffness of the reinforcement and inclination angles of the backfill material on the acceleration amplification factors, the lateral displacement of the wall, surface settlement of the backfill, the values and distributions of static and dynamic earth pressures along the height of MSE wall and tensile loads on the polymeric geostrip reinforcement were investigated. According to the information obtained, it has been seen that traditional pseudo static limit equilibrium equations lead to overestimated values for MSE wall. Thus, two different pseudo static limit equilibrium equations have been proposed to designers in order to calculate total force acting on the polymeric geostrip reinforced MSE walls. It was observed that the failure surface geometries recommended by current design codes for geosynthetic materials are not suitable for polymeric geostrips. Increasing the inclination angle of the backfill material and stiffness of the reinforcement result in the increase of static and dynamic earth pressures, amplification factors and tensile loads on the reinforcement. The effect of stiffness of the reinforcement and inclination angle on the failure surface is negligible. In addition, dynamic soil parameters of MSE walls reinforced with polymeric geostrip were determined in accordance with the data obtained from the experimental study. The results obtained from the experimental study were compared with the finite element model.

Ini adalah preview Form Pengujian Konsistensi Aterberg
dalam hal ini mencakup metode Uji Batas Cair, Batas Plastis dan Indeks plastisitas suatu Komponen tanah.

Dalam Pelangksanaan nya terkadang Kesalahan Praduga dengan menggunakan Log dengan 2 sampel Memberikan Bias Yang cukup signifikan. oleh sebab itu Batas cair sebaiknya menggunkan beberapa variasi ketukan agar mendapatkan hasil yang presisi.

The paper deals with the laboratory testing of coarse-grained soils that are reinforced using a geogrid. The shear strength properties were determined using a large-scale direct shear test apparatus. The tests were executed on original as well as on reinforced soil, when the geogrid was placed on a sliding surface, which permitted determining the shear strength properties of the soil-geogrid interface. The aim of the tests was to determine the interface shear strength coefficient α, which represents the ratio of the shear strength of the soil-geogrid interface to the unreinforced soil. The tests were executed on 3 samples of coarse-grained materials, i.e., poorly graded sand, poorly graded fine gravel and poorly graded medium gravel. Two types of geogrids were tested, i.e., a woven polyester geogrid and a stiff polypropylene geogrid. The results of the laboratory tests on the medium gravel showed that the reduction coefficient α reached higher values in the case of the stiff polypro...

Soil erosion is a natural process that is intensified by human activities. Experts of natural resources consider soil erosion as a phenomenon that has caused the destruction of civilizations. Preventing erosion and actually reducing its damages to the natural level of soil losses depends on choosing appropriate strategies for soil protection. Preventing erosion and actually reducing its damages to the natural level of soil losses depends on choosing appropriate strategies for soil protection. Among the many methods of preventing soil erosion and increasing the stability of slopes, bio-engineering methods of protected areas have received a lot of attention due to environmental and economic issues in engineering today. In this research, the effect of the root of Celtis caucasica and Pistacia atlantica in soil reinforcement around the Kalan Dam, 34 km southwest of Malair City, was investigated on different slopes. To carry out this study, two species of Celtis caucasica and Pistacia atlantica were investigated in three different populations in three areas with low (0-10 %), medium (10-25 %), and high slopes (25-40 %). The root samples were collected on December 15, 2021, from a depth of about 30 cm. In general, 6 individual trees were randomly selected in each area and all the characteristics of the soil were examined in 6 repetitions and the root in 10 repetitions (to test the tensile strength of the roots). The treatment used to preserve and prepare the roots includes washing and placing them in plastic bags containing a 15 % alcohol solution. Then samples with a length of about 10 cm were randomly selected and the speed of the tensile strength test was 10 mm min -1 . The root was measured using a standard Instron device manufactured by the Santam factory. Considering the normality of the data, the t-test was used to compare the two species. Three harvesting areas with different slope classes, including low (Region 1), medium (Region 2), and high (Region 3) slopes. The treatment used to preserve and prepare the roots includes washing and placing them in plastic bags containing a 15 % alcohol solution. Then samples with a length of about 10 cm were randomly selected and the speed of the tensile strength test was 10 mm min -1 . The root was measured using a standard Instron device manufactured by the Santam factory. Considering the normality of the data, the t-test was used to compare the two species. In three harvesting areas with different slope classes, including low (Region 1), medium (Region 2), and high (Region 3) slopes, 18 stems of Callaghan and 18 stems of P. atlantica were harvested for root Callaghan, and 18 stems of P. atlantica were harvested for root sampling. The results showed that the root elasticity of C. caucasica is higher than P. atlantica. The relationship between the diameter and root reinforcement was different, and about C. caucasica it was negative. the highest root reinforcement is related to fine roots. The RAR (Root Area Ratio) in C. caucasica was higher on a high slope rather than a low slope. In steep slopes (Region 3) root tension of C. caucasica is higher than the area with the average slope. There was a positive correlation between PL and LL of soil in C. caucasica stand in Region 3. Finally, strengthen the soil and reduce erosion in the upper slopes. The noteworthy point is that the percentage of carbon in the soil in Region 3 is higher than in the other two regions, which is due to the negative correlation between carbon and sand in the soil. C. caucasica in high-slope lands with a lower percentage of sand causes an increase in carbon deposition and parameters of the dough limit and liquid limit of the soil. According to the results of the data, the amount of root elasticity of C. caucasica is higher than P. atlantica species. The relationship between diameter and root tension is different in the case of species. About C. caucasica it was negative and the highest root tension is related to the roots of the fine roots, but in P. atlantica, the relationship between diameter and tension is a positive power function and As the diameter increases, the amount of tension increases. The amount of root area ratio (RAR) in C. caucasica is higher on the higher slope than on the lower slope. The percentage of clay in the soil texture has a negative correlation with the amount of RAR, and root growth and distribution are less in clay soils. C. caucasica in high-slope lands with lower sand percentage increases carbon deposition and parameters of the plastic limit and liquid limit of the soil. It is suggested to use species that increase soil reinforcement and reduce the amount of erosion in the area of the dam in order to reduce the amount of erosion and increase the useful life. according to the results, it can be recommended that it is better to use C. caucasica in afforestation around the Kalan Dam because of its greater effect in increasing soil improvement and reducing erosion.

Soil erosion is a natural process that is intensified by human activities. Experts of natural resources consider soil erosion as a phenomenon that has caused the destruction of civilizations. Preventing erosion and actually reducing its damages to the natural level of soil losses depends on choosing appropriate strategies for soil protection. Preventing erosion and actually reducing its damages to the natural level of soil losses depends on choosing appropriate strategies for soil protection. Among the many methods of preventing soil erosion and increasing the stability of slopes, bio-engineering methods of protected areas have received a lot of attention due to environmental and economic issues in engineering today. In this research, the effect of the root of Celtis caucasica and Pistacia atlantica in soil reinforcement around the Kalan Dam, 34 km southwest of Malair City, was investigated on different slopes. To carry out this study, two species of Celtis caucasica and Pistacia atlantica were investigated in three different populations in three areas with low (0-10 %), medium (10-25 %), and high slopes (25-40 %). The root samples were collected on December 15, 2021, from a depth of about 30 cm. In general, 6 individual trees were randomly selected in each area and all the characteristics of the soil were examined in 6 repetitions and the root in 10 repetitions (to test the tensile strength of the roots). The treatment used to preserve and prepare the roots includes washing and placing them in plastic bags containing a 15 % alcohol solution. Then samples with a length of about 10 cm were randomly selected and the speed of the tensile strength test was 10 mm min -1 . The root was measured using a standard Instron device manufactured by the Santam factory. Considering the normality of the data, the t-test was used to compare the two species. Three harvesting areas with different slope classes, including low (Region 1), medium (Region 2), and high (Region 3) slopes. The treatment used to preserve and prepare the roots includes washing and placing them in plastic bags containing a 15 % alcohol solution. Then samples with a length of about 10 cm were randomly selected and the speed of the tensile strength test was 10 mm min -1 . The root was measured using a standard Instron device manufactured by the Santam factory. Considering the normality of the data, the t-test was used to compare the two species. In three harvesting areas with different slope classes, including low (Region 1), medium (Region 2), and high (Region 3) slopes, 18 stems of Callaghan and 18 stems of P. atlantica were harvested for root Callaghan, and 18 stems of P. atlantica were harvested for root sampling. The results showed that the root elasticity of C. caucasica is higher than P. atlantica. The relationship between the diameter and root reinforcement was different, and about C. caucasica it was negative. the highest root reinforcement is related to fine roots. The RAR (Root Area Ratio) in C. caucasica was higher on a high slope rather than a low slope. In steep slopes (Region 3) root tension of C. caucasica is higher than the area with the average slope. There was a positive correlation between PL and LL of soil in C. caucasica stand in Region 3. Finally, strengthen the soil and reduce erosion in the upper slopes. The noteworthy point is that the percentage of carbon in the soil in Region 3 is higher than in the other two regions, which is due to the negative correlation between carbon and sand in the soil. C. caucasica in high-slope lands with a lower percentage of sand causes an increase in carbon deposition and parameters of the dough limit and liquid limit of the soil. According to the results of the data, the amount of root elasticity of C. caucasica is higher than P. atlantica species. The relationship between diameter and root tension is different in the case of species. About C. caucasica it was negative and the highest root tension is related to the roots of the fine roots, but in P. atlantica, the relationship between diameter and tension is a positive power function and As the diameter increases, the amount of tension increases. The amount of root area ratio (RAR) in C. caucasica is higher on the higher slope than on the lower slope. The percentage of clay in the soil texture has a negative correlation with the amount of RAR, and root growth and distribution are less in clay soils. C. caucasica in high-slope lands with lower sand percentage increases carbon deposition and parameters of the plastic limit and liquid limit of the soil. It is suggested to use species that increase soil reinforcement and reduce the amount of erosion in the area of the dam in order to reduce the amount of erosion and increase the useful life. according to the results, it can be recommended that it is better to use C. caucasica in afforestation around the Kalan Dam because of its greater effect in increasing soil improvement and reducing erosion.

One of the main factors that lead to the reduction of the potential, electric field distribution and the insulating level is surface charge accumulation on insulators .In this paper, the effect of surface charges on potential and electric field distribution along an outdoor polymeric insulator under DC voltage is studied by computer simulations. Research has shown that the accumulation of electrical charges on the surface of insulators can affect the performance of the flashover. So to avoid the occurrence of unexpected flashover must have a thorough understanding of surface charge to be examined its impact on insulation performance under various stresses. In this current paper, electric field and potential distribution along standard polymeric insulator with different geometry were investigated in the presence of surface charges. Calculations of the potential and electric field are performed based on Finite Element Method (FEM). Numerical simulations were carried out in COMSOL Multiphysics® to study the effect of the positive and negative surface charges on potential distribution under DC positive and negative applied voltage. Simulation results show the importance of surface charges effect in potential and electric field variations and the performance of the flashover.

Soft ground improvement to provide stable foundations for infrastructure is national priority for most countries. Weak soil may initiate instability to foundations reducing their lifespan, which necessitates the adoption of a suitable soil stabilization method. Amongst various soil stabilization techniques, using appropriate admixtures is quite popular. The present study aims to investigate the suitability of bagasse ash and stone dust as the admixtures for stabilizing soft clay, in terms of compaction and penetration characteristics. The studies were conducted by means of a series of laboratory experimentations with standard Proctor compaction and CBR tests. From the test results it was observed that adding bagasse ash and stone dust significantly upgraded the compaction and penetration properties, specifically the values of optimum moisture content, maximum dry density and CBR. Comparison of test results with available data on similar experiments conducted by other researchers were also performed. Lastly, a study on the cost effectiveness for transport embankment construction with the treated soils, based on local site conditions in the study area of Assam, India, was carried out. The results are analyzed and interpreted, and the relevant conclusions are drawn therefrom. The limitations and recommendations for future research are also included.

Significant soil liquefaction effects were observed in the urban area of La Isla San Lorenzo following the Mw 6.1 earthquake that occurred on July 30, 2021, in northern Peru. The epicenter was located 12 km west of the city of Sullana, in the Piura region, an area characterized by alluvial deposits and a shallow water table, which contribute to high liquefaction potential. These effects were manifested through the formation of sand boils, ground fissures, and water ejection, leading to visible ground instability and potential damage to infrastructure. To assess the liquefaction potential in the affected area, a geotechnical analysis was performed using both empirical and numerical methods. The classical liquefaction potential method by Seed and Idriss (1971) was applied to evaluate the factor of safety against liquefaction, indicating the presence of liquefiable soil layers down to a depth of 8m. Additionally, a one-dimensional (1D) numerical analysis was conducted using the PDMY02 constitutive model by Elgamal (2002), which simulates the cyclic behavior of sandy soils under seismic loading. This model, based on a pore pressure ratio threshold, identified liquefaction triggering up to a depth of 6 m. Furthermore, shear strain analysis confirmed the occurrence of significant deformations associated with liquefaction. The combined results of empirical and numerical approaches highlight the vulnerability of La Isla San Lorenzo to liquefaction hazards, emphasizing the need for improved site-specific seismic hazard assessments and mitigation measures in future urban planning and infrastructure development.

One of the main factors that lead to the reduction of the potential, electric field distribution and the insulating level is surface charge accumulation on insulators .In this paper, the effect of surface charges on potential and electric field distribution along an outdoor polymeric insulator under DC voltage is studied by computer simulations. Research has shown that the accumulation of electrical charges on the surface of insulators can affect the performance of the flashover. So to avoid the occurrence of unexpected flashover must have a thorough understanding of surface charge to be examined its impact on insulation performance under various stresses. In this current paper, electric field and potential distribution along standard polymeric insulator with different geometry were investigated in the presence of surface charges. Calculations of the potential and electric field are performed based on Finite Element Method (FEM). Numerical simulations were carried out in COMSOL Mult...

Untuk mengatasi kelongsoran pada lereng, dapat dilakukan berbagai cara untuk memperkuat lereng.  Lereng yang memiliki daya dukung rendah dapat diperkuat dengan geogrid.  Penambahan geogrid inilah yang memungkinkan untuk membangun bangunan di atas lereng.  Berbagai macam penelitian dibutuhkan karena banyaknya faktor yang mempengaruhi kekuatan dari lereng menerima beban. Pada penelitian ini dilakukan pengujian terhadap 12 model lereng.  Model yang dibuat berupa lereng pasir dengan ketinggian 70 cm.  Pengujian ini dilakukan pada box ukuran 115 × 100 × 100 cm.  Pembebanan disalurkan melalui pondasi, tipe pondasi yang digunakan adalah pondasi menerus.  Kepadatan model direncanakan, dengan nilai RC 85%.  Sudut kemiringan dalam model lereng yang diuji sebesar 56 o .  Data yang diperoleh dari penelitian ini adalah daya dukung lereng dari variasi banyaknya lapisan geogrid yang dipakai (n), variasi lebar pondasi dan jarak tepi lereng (d/B=1).  Dari data yang ada dibandingkan antara lereng tan...

Indonesia is a tropical country threatened by many disasters, such as earthquakes and other collateral hazards (liquefaction). Utilization of micro pile on the liquefaction prone areas is quite popular to increase the soil bearing capacity. In this research, Eucalyptus Pellita Timber was used as micro-piles alternatives. This study aims to determine the effect of timber pile addition on soil settlement and the increase in bearing capacity. Some laboratory investigations were conducted, such as timber and soil physical and mechanical characteristics, preloading tests, and seismic load tests by using small-scale shaking table test. The preloading tests were carried out for 40 days, and the settlements were recorded every 24 hours. Subsequently, seismic load tests were conducted on sandy soil with Dr = 40%. The seismic duration was 37 seconds, with PGA = 0.3 g and f = 0.78 Hz. The preloading test results show that Eucalyptus pellita timber piles are able to reduce the settlement by 18%. and from seismic load testing results are able to reduce the settlement by 68% due to earthquake loads with PGA = 0.3g and a frequency of 0.78 Hz on sandy soil with the potential for liquefaction. This is due to the resistance at the tip of the pile and the skin friction on the timber pile. So, from the results of the model test, it shows that the use of Eucalyptus Pelita timber piles can be used as an alternative to handling sandy soils in areas where liquefaction has the potential to occur.

The circular economy encourages the production and consumption of sustainable embankment geomaterials and their blends utilizing recycled waste materials in roads, railway tracks, airfields, and underground structures. Geomaterials comprising high-plastic soft expansive clay pose excessive settlement during cyclic traffic/railway/airfield loading resulting in uneven geometry of overlying layers. This paper demonstrates multiobjective optimized improvement of expansive clay (C) geotechnical characteristics by cost-effective agro-wastes additives at microlevel (by 3% to 12% rice husk ash, i.e., RHA), nanolevel (by 0.6% to 1.5% rice husk derived green nano-SiO2, i.e., NS), and synergistic micro to nanolevel (NS-RHA). The swell potential, resilient modulus (MR), initial elastic modulus (Es), unconfined compressive strength (UCT), and California bearing ratio (CBR) of C and its blends were determined. The chemical characterization of C and its blends were conducted through Fourier transf...

Türkiye'de ki 1999 Marmara depremi sonrası bilim otoritelerinin ortaya koyduğu gerçekler, Türkiyede'ki yapı stoğunun hızlı bir şekilde yenilenmesi gerekliliğini gündeme getirmiştir. Bu çerçevede hızlı bir kentsel dönüşüm süreci başlatılmış ancak bu sürecin sonunda ortaya çıkacak inşaat yıkıntı atıkları için yapılan planlamalar yetersiz kalmıştır. Kentsel dönüşümden meydana gelecek atıkların doğaya terkedilmeleri çevre kirliliğine sebep olacağı ve bu atıklar büyük hacimlerinden dolayı depolama problemi olduğu gerçeği gündeme gelmiştir. Bu sorunlara çözüm olarak, bu atıkların geri kazanımı bir çözüm olarak düşünülebilir. Killi zeminlerin yol alt tabakasında olduğu durumlarda stabilizasyon problemleri ortaya çıkmakta ve bu sorun farklı zemin iyileştirmeleri ile düzeltilmeye çalışılmaktadır. Bu çalışmada söz konusu inşaat atıklarının, killi zeminlerde zemin stabilizasyonuna etkisini incelemek amacı ile yıkıntı atıklarının zeminlerin serbest basınç dayanımına etkileri araştırılmıştır. Çalışmada doğal zemin numunesi olarak kabul edilen kaolen kiline değişik oranlarda inşaat yıkıntı atığı katılarak örnekler numuneler hazırlanmıştır. Bu zemin örneklerine serbest basınç deneyi yapılarak mukavemetlerinin ne kadar arttığı belirlenmiştir.

Retaining walls which prevents soil surface elevation difference are structural engineering for slope stability. These constructs are under the effect of earth pressure. Retaining wall which is built in the zone of earthquake under the dynamic effect as well as static effect. These two forces must be taken into the design stage. In this study, is calculated by the method of calculation of earth pressure Rankine earth pressure theory on sample application for sizing, drainage, materials used, etc. determination of such as parameters to demonstrate the significance of the engineering predictions. Sample retaining wall calculations were made according to the Rankine theory wall, it has brought into compliance with the Regulations.

Kendisi için elverişsiz veya yetersiz bir zemine oturan mühendislik yapısının, oturduğu zemini daha verimli kullanma yollarından birisi zemin içerisinde kazık imalatı yapmaktır. Büyük ölçekli yapılarda kazık taşıma gücünü hatalı belirlemek aşırı dizayna veya güvensiz tarafta kalmaya neden olabilmektedir. Bu nedenle kazıkların zemin ve/veya kaya ortam içerisindeki taşıma gücünü gerçeğe yakın bir biçimde belirlemek gerek yapı güvenliği gerekse ekonomi açısından önem taşımaktadır.Bu çalışmada, SPT deneyinden kazık nihai taşıma gücü veren teorik yöntemler ile matematiksel modele dayalı kazık yükleme deneyi değerlendirme yöntemleri karşılaştırılmıştır. 8 adet kazık yükleme deneyi; SPT deneyine dayanan teorik yöntemler ve matematiksel modele dayalı kazık yükleme deneyi değerlendirme yöntemleri ile tahlil edilmiştir. Teorik SPT yöntemleri ve kazık yükleme deneyi değerlendirme yöntemleri iki ayrı blok olarak kıyaslanmıştır.

The development of a nation partially depends on sustainable materials obtained from agricultural products. Increased agricultural products could increase the amount of waste generated yearly. This paper presents a review on the use of agricultural waste with pozzolanic properties (rice husk ash, Locust bean waste ash, Palm oil fuel ash, Banana leaf ash, Bagasse ash, Coconut shell ash, Bamboo leaf ash, Corn cob ash, Cassava peel ash and Palm kernel shell ash) in various geotechnical engineering applications. Interestingly, these wastes were subjected to various laboratory tests such as (particle size distribution, Compaction, Atterberg, unconfined compressive strength (UCS) and California bearing ratio (CBR)) to assess their effectiveness in soil improvement. In all these, the percentages of the materials required for soil improvement were discussed. The reports from various researchers have shown that agricultural waste having pozzolanic properties improves the engineering properti...

Tanah ekspansif merupakan salah satu jenis tanah bermasalah, sangat peka tehadap perubahan kadar air. Tanah ini mempunyai ciri-ciri kembang susut yang besar akibat dari perubahan volume pori yang dapat menimbulkan gaya angkat terhadap konstruksi yang ada sehingga dapat menimbulkan kerusakan pada konstruksi tersebut. Tujuan penelitian ini untuk mengetahui kapasitas tarik prototipe angkur tanah bersayap penampang segi empat dimensi 7 cm pada pasir, tekanan pengembangan tanah ekspansif pada tabung baja dimensi ukuran 75 cm x 25 cm, dan efektivitas penggunaan angkur tanah bersayap penampang segi empat dimensi 7 cm dalam menahan gaya pada tanah ekspansif. Material yang digunakan dalam pengujian ini adalah pasir dan tanah ekspansif yang diambil dari Sambungmacan, Sragen, Jawa Tengah. Alat uji utama yang digunakan dalam pengujian ini berbentuk tabung silinder baja. Angkur tipe box bersayap dengan ukuran 7x7x30 cm ditanam di dalam tabung silinder yang berisi pasir kedalaman 75 cm pada lapisan bawah dan tanah ekspansif kedalaman 25 cm di lapisan atasnya. Tanah ekspansif diberi air untuk diketahui pengaruhnya dalam nilai pengembangan. Kesimpulan yang diperoleh bahwa kapasitas tarik ultimit angkur pada pasir kedalaman 90 cm sebesar 815 kg dan pada pasir kedalaman 100 cm sebesar 1.120 kg. Tekanan pengembangan tanah ekspansif yang diperoleh pada tabung baja dimensi ukuran 75 cm x 25 cm adalah sebesar 2.298 kg saat kondisi kadar air 50%. Pengembangan tanah saat kadar air 50 % pada kondisi free-swelling sebesar 67,23 mm dan pada kondisi swelling tanah tertahan angkur sebesar 6,43 mm.

Tanah lempung memiliki daya dukung yang rendah pada kondisi muka air yang tinggi, sifat kembang susut (swelling) yang besar dan plastisitas yang tinggi. Hal tersebut mengakibatkan kerusakan pada struktur bangunan di atas tanah seperti jalan bergelombang, retak, dan penurunan. Dikarenakan kerugian dari akibat kembang susut tanah, maka diperlukan stabilisasi untuk mengurangi kembang susut dan meningkatkan daya dukung tanah. Tujuan dari penelitian ini untuk mengetahui pengaruh tanah lempung terhadap limbah marmer dan bubuk arang kayu. Hasil dari pengujian ini didapatkan nilai CBR desain dengan tanah asli (tanpa bahan tambah) dengan tanah asli dicampur 15% limbah marmer dan 5%, 10% dan 15% bubuk arang kayu dengan hasil sebesar 9,5%; 15,3%; 16,9%; 19,1; dan 21,2%. Hasil optimum yang diperoleh pada penelitian ini adalah pada persentase tanah asli ditambah 15% limbah marmer dan 15% bubuk arang kayu dengan kenaikan nilai CBR desain sebesar 123,16% (dari nilai CBR tanah asli 9,5% menjadi 21,2%). Dapat diperoleh kesimpulan bahwa pengujian tanah lempung dengan bahan tambah limbah marmer dan bubuk arang kayu dapat meningkatkan kemampuan tanah menuju keadaan yang lebih stabil ditandai dengan meningkatnya nilai CBR.

This paper deals with the soil improvement under the tower cranes. Near to the Sport Hall structure for the needs of the construction three cranes with 120 tone-meter weight capacity were erected. Based on need to reduce the tampon layer and digging near to the hall foundation soil improvement using the geosynthetics is made. PLAXIS analysis with the maximum applied loads was made. After the cranes construction settlements are measured on the three cranes, two of them are improved with geosynthetics. The measured settlements are compared with the calculated one. Measured settlements were less then calculated. On that base, the discussion is made on justification using geosynthetics in the case of soil improvement under the heavy cranes. The load history and soil consolidation is also a big issue in settlement analysis for these types of structures. The influence of the geosynthetics on settlements is other issue discussed in the paper.

Paper deals with the problem of foundation on the soft soil in seismic active regions. In these regions special measures for foundation and sub-base preparation must be taken. Our company deals a lot with soil improvement in loose and soft soils with high ground water levels. The special technique for soil improvement using geosynthetics is developed. The foundation on this soil is problematic and the soil characteristic must be taken into consideration in the early phase of the structural design. The whole structure, taking into consideration the structure stiffness, must be modeled and examined in static and dynamic loads. Structure is modeled by Plaxis software, with subsoil and improved tampon layer and geosynthetics layer(s) between the subsoil and tampon layer. The earthquake response for real earthquake input is analyzed. The stresses, strains and deformations are analyzed in soil and synthetics layers. Experiences not only from analysis but from constructions of the improvement from several sites are discussed and illustrated in the paper. As a result of our analysis and long years of theoretical and practical experience the recommendations for shallow foundations soil improvement are given.

Considering that the infrastructures in different regions experience different weather cycles that can lead to the creation of minor surface cracks to be noticeable, it is necessary to understand the durability behavior of soils. Although previous studies have extensively investigated the strength behavior of oil-contaminated soil, there is still no accurate understanding of the durability of oil-contaminated soil against wet-dry cycles. To fill these gaps, this research is focused on the durability characteristics of oil-contaminated soils. For this purpose, a series of laboratory tests were conducted to evaluate compaction, durability and microstructural analyses. In that regard, the soil was contaminated with oil in concentrations of 4, 7 and 10% and then stabilized with lime and cement in concentrations of 0, 3, 6 and 9% separately. Initial laboratory experiments, including Atterberg limits and compaction tests, were conducted. Subsequently, durability tests were performed to examine wet-dry cycles in 1, 3, and 6 cycles on oil-contaminated soil samples, as well as those stabilized with cement and lime. The results demonstrated that the highest durability was observed in the samples containing 4% oil and 9% cement in the 6th cycle, showing a 42% increase in resistance compared to a similar sample with the same percentage of oil and cement in the 3rd cycle. Additionally, the elasticity modulus of the oil-contaminated soil sample with 4% oil and stabilized with 6% lime was 2 times that of the 1st cycle in the 3rd cycle and 2.8 times that of the 3rd cycle in the 6th cycle. Microscopic analysis using electron field emission microscopy unveiled that the incorporation of cement and lime as stabilizing agents resulted in a denser and more compact structure of oil-contaminated soil. This comprehensive research endeavor seeks not only to advance the management practices of contaminated soils but also to uphold the conservation of natural resources while offering an alternative solution for the construction of secondary access roads.
Keywords
Wet-dry cycles  stabilization  durability  oil-contaminated soils  oil spill

Collapsible soils are robust in their natural, dry state but exposure to water leads to decomposition. They also undergo large volumetric changes often associated with the detachment of the ground surface. The construction on such type of soils is challenging duet to their costly need for treatment. Gypseous soil is considered one of the important collapsible soils and is typically found in desert and semi-arid areas with widespread moisture deficits. This study investigates the effect of fly ash as an amendment on the compressibility and shear strength of gypseous soil. A 51.23% of gypsum content is found in the soil samples collected from the city of Tikrit in the Salah al-Din governorate of Iraq. Fly ash is added at percentages of 4, 8, 12, 16, and 20% of the soil's weight. Direct shear and collapse laboratory tests are executed on both natural and treated soil. The findings demonstrated that the treated soil exhibited a significant increase in both cohesion and the angle of internal friction, and a decreased value of the Collapse Potential (CP). The collapsibility can be limited to 55.29% with a 20% addition of fly ash. The cohesion and internal friction angle are improved by 53.48% and 81.47%, respectively. Finally, the ideal percentage of fly ash ranges between 12% and 16%, as the enhancing ratio for both the collapse and the soil's shear strength significantly decreases beyond this percentage.

In this paper improvement of the soil foundation for 9 th story building is elaborated. Problem is solved using grid footing on replaced tampon material reinforced with geosynthetics. Bad subsoil is replaced with tampon soil with good geomechanical characteristics, wrap with geotextiles and geogrids. For quickening the consolidation wells are used. The deformation and stresses are calculated using Plaxis software. Calculated large settlements are measured during the building.

This paper presents the results of a series of large scale direct shear tests carried out using sand and geogrid to appraise the contribution of shear resistance at interfaces between soil-soil, soil-geogrid and the soil-transverse ribs of a geogrid during the test.Soil samples used are with varying proportions of Sand, 6mm aggregates and 12mm aggregates at different densities. The study results revealed that the transverse ribs contribute 17% of the total interface resistance for soil samples tested with the geogrid. From the test results it is observed that the shear strength at sandgeogrid interface mobilized under direct shear mode is depending on thedensity, size of the particles and thickness of ribs. Moreover, it is observed that the passive resistance contributed by ribs found decreasing with increase of normal load and the passive resistance found decreasing with decreasing of density Copy Right, IJAR, 2019, All rights reserved.

Increase of impervious surfaces in urban areas, has led to many problems, including flooding roads and streets during rainstorms which could create difficulties for pedestrians and cars. An effective way of reducing urban runoff and waterlogging is to use permeable concrete pavement. In the present study, the effect of replacing different percentages of travertine additive with the main aggregates of permeable concrete on physical and mechanical properties of this type of concrete has been studied. Samples development and testing with three replicates for each sample was carried

Here, the sensitivity of the Casimir force in a three-layer microsystem is investigated by considering a ferrofluid as the middle layer and plates with different optical properties via Lifshitz theory. The plate materials are made of gold (Au), silica (SiO2), and silicon carbide (SiC) to cover a wide range of conductivity. It is observed that by changing the plates from a good conductor to a poor conductor, the magnitude of the Casimir force decreases significantly, and if the gap between the plates is filled with a liquid layer, this decrease is even greater. The results show that the presence of a ferrofluid, formed by adding ferric oxide (Fe3O4) magnetic nanoparticles to kerosene (C12H26-C15H32), leads to a reduction in the Casimir force. Moreover, increasing the nanoparticle concentration (at a constant diameter) causes a significant decrease in the Casimir force, while increasing the nanoparticle diameter (at a constant concentration) strengthens the Casimir force. The results indicate that the optical properties of the plates have a significant impact on this behavior. It has also been observed that at a fixed distance between the plates, the addition of magnetic nanoparticles with a specific diameter has no effect on the magnitude of the Casimir force compared to the case where the middle layer of fluid is nonmagnetic, and considering this point is very important in the design of microelectromechanical systems (MEMS) that operate under magnetic effects.

Granular columns are commonly used for ground improvement. However, minimal research is presently available on the effect of backfill particle size on the geotechnical performance of granular column-reinforced soil. Geo-environmentally, using crushed waste glass (CWG) as a sustainable replacement for depleting traditional construction sands could offer a cleaner feedstock to backfill granular columns while helping recycle growing stockpiles of waste glass, potentially supporting the circular economy transition and decarbonisation of the construction industry. Given these multi-pronged motivations, this study investigated the shear strength and consolidation behaviour of kaolin reinforced with a CWG granular column. Three different particle size ranges (PSR) of CWG were discretely used to install a granular column in the kaolin bed, including fine (0.50-1.0 mm), medium (1.0-1.7 mm) and coarse (1.7-3.35 mm) particles with median particle sizes of 0.78 mm, 1.42 mm and 2.30 mm, respectively. The geocomposite containing a medium CWG column showed the highest increase in friction angle, increasing from 14.0° for kaolin only specimens to 20.7° for the geocomposites. Similarly, the consolidation The Video Abstract has been updated.

In this paper, a study has been carried out to estimate the ultimate capacities of concrete circular piles which are used as foundation type due to reasons such as poor ground conditions, seismicity, high or irregular loads etc. by field tests. Two cone penetration tests (CPTU), which measure the pore water pressures on alluvial soils of the Adapazarı plain, were conducted at the same locations with drillings which SPT tests were carried out. Ultimate capacities of a single pile with a specific geometry were determined by the methods proposed in the literature by using the data obtained from SPT and CPT field tests at both points. According to this, it is concluded that pile capacities can give very different results even in short distances in regions which offer sudden layer changes in horizontal and vertical. Disadvantages of the SPT test in practice compared to CPT have been shown to cause also different values of pile capacities.

Jenis-jenis geosintetik yang telah banyak digunakan dalam rekayasa geoteknik. Dalam penggunaan yang permanen, kinerja jangka panjang struktur bergantung pada keawetan atau daya tanah geosintetik. Bergantung pada penerapannya, geosintetik dapat mempunyai spesifikasi khusus, seperti ketahanan terhadap rayapan (creep), tempratur atau sinar ultra violet. Bahan-bahan dasar geosintetik, terutama terdiri dari elemen-elemen karbon, hydrogen dan kadang-kadang nitrogen serta chloride (PVC). Jenis-jenis geosintetik yang telah banyak digunakan dalam rekayasa geoteknik, adalah: Geotekstil; Geogrid; Geomembran; Geokomposit; Geonet; Geosynthetic Clay Liner; dan lain-lain. Dalam mengevaluasi perancangan geosintetik dan kinerjanya adalah mengidentifikasi fungsi relative untuk penggunaannya. Mengidentifikasi factor-faktor yang mempengaruhi kinerja geosintetik, dan menentukan sifat-sifat geosintetik yang dibutuhkan. Spesifikasi singkat sifat-sifat fungsi geosintetik yang disyaratkan, prosedur pemasangan dan penyimpanannya merupakan hal yang penting untuk meyakinkan bahwa kualitas geotekstil yang dikirim serta pemasangan nantinya seperti yang dikehendaki. Sifat-sifat geosintetik dapat berubah secara merugikan, sebagian oleh pengaruh waktu, kelelahan, kerusakan mekanis, hidrolis, serangan bahan kimia dan biologi, dan sebagainya. Untuk ini, maka factor reduksi kekuatan harus diperhitungkan dalam perancangan.

The use of geosynthetics as basal reinforcement in piled embankment is growing in Europe. An experimental embankment at full scale realised during the French national project (ASIRI) and a real instrumented job allow highlighting the task and the behaviour of these materials in the load transfer platform.

Significant portions of the Earth's surface are covered with soils, and when they eventually get saturated with water, they may experience significant changes in volume. These materials are called collapsible soils. Gypsum rocks are formed as a result of the evaporation of salt water from lakes formed in desert or semidesert areas. The implication of steel slag as a modifier on the compressibility and shear strength of gypseous soil was investigated in this work. Samples of soil with a 53.36% gypsum concentration were acquired from Tikrit, located in the Salahaldeen province of Iraq. Steel slag was added in proportions of 3%, 6%, 9%, 12%, and 15% by weight of the soil. Collapse and direct shear tests were conducted for both natural and treated samples. According to the research findings, the treated soil has significantly higher degree of cohesion and an angle of internal friction, and the Collapse Potential (CP) value has substantially dropped. This enhancement can reach up to 69.28% at 15% treatment for collapse potential, which represents the best weight ratio for the additive. The cohesion and angle of internal friction increased to 155.41% and 82.0%, respectively, with 15% treatment for the direct shear test.

Soil, aggregate, bitumen, concrete, steel, and sand are some of the various materials used in highway construction. Every material has specific desirable qualities that are appropriate for its intended function. Properties including soundness, hardness, G.I. value, crushing strength, and water absorption capacity are all examined when studying roadway materials. Highway materials are characterized using laboratory experiments and field testing. Pavement testing and evaluation is an important part of highway design because it affects the safety, durability, and performance of the road. To create a safe highway, three main factorshuman, vehicular, and roadway-as well as their interactions must be taken into account. Human aspects include car-following behaviour, visual acuity for the traffic signs and signals, and reaction time for the steering and braking. In this project we can briefly study about chemical and physical properties of highway material. The highway material include soil, sand, bitumen, aggregate, steel, cement, this different material has different properties which is very important for the strong and durable highway construction. Soil is the main part of highway construction in this project we can test the bearing ratio of soil by using California Bearing Ratio method. This method is mainly utilized to know the strength of soil at the particular location where we have to construct the infrastructure. CBR values and soil type The soil sample's CBR value directs how hard the surface is. For example, clay typically has a CBR value of 2 %, but other sands can have a CBR value of 10 %. A high-quality sub-base has a CBR value among 80 and 100 %.