Unified Soil Classification System Research Articles

Spatial Variation of Silt and Clay Sediment Deposit in Bhaktapur City

3D geological subsurface model of the Bhaktapur City is prepared using RockWork2016, which is based on 3-D Geo-scientific information system (3-D GSIS). The main aim of this study is to interpret the geological conditions of Bhaktapur city, providing subsurface geological database and its relevance to 2015 Gorkha earthquake damages. For this, the borehole data are collected from different sources and digitized in the RockWork2016 program for the generation of the 3-D attributed subsurface model. For the stratigraphy divisions of the soil, the unified soil classification system is used. From the interpretation of the developed attributed model, it is found that the central part or the core area of the Bhaktapur city has a deeper depth of the soft sediment-silt and clay rather than other surrounding parts of the city. This indicates the possibility of local soil amplification in the central part of the study area. The spatial variation of the subsurface sediment deposit is then co-relate with damage scenario caused by 2015 Gorkha earthquake.

Horizontal and Vertical Geotechnical Variations of Soils According to USCS Classification for the City of An-Najaf, Iraq Using GIS

The unified soil classification system (USCS) first proposed by Casagrande and subsequently developed by the Army Corps of Engineers. It widely used in many building codes and books. An-Najaf city is the most important city in Iraq due to its religious and spiritual value in the Muslim world, so it is fast expanding and continuous developing city in Iraq. The data from 464 boreholes in the study area for depths of 0–26 m have been used. 13 Soil samples were collected from each borehole with 13 depths level (0–26) m with 2 m intervals. The USCS was applied to the soil samples from 13 depth levels borehole. This research aims to create a geodatabase for soil properties for An-Najaf. The ArcGIS 10.5 software was used to interpolate the spatial data to produce 33 geotechnical maps for fine soil, coarse soil and USCS for 13 depth levels. For numerical soil data, Ordinary Kriging has been used for interpolation mapping of Fine and Coarse percentage data for each depth. For non-numerical (nominal) soil data (USCS class), the Indicator Kriging method is used. The results show that the coarse soil occupied 85–95% for depth 0–16 m and consist of (SP, SP-SM, SM) while fine soil occupied 5–15% consisting of (OL, CH, ML) subsequently, this soil when compacted has a permeability of pervious to semi impervious, good shearing strength, low to very low compressibility and acceptable workability as a construction material. The results also show that after 16 m depths until 26 m, the fine soil percentage increased to 40% with a coarse soil percentage of 60%, indicating changes in soil characteristics as the permeability became semi-pervious to impervious, fair shearing strength, medium compressibility and fair workability as a construction material. The study results will provide help and saving time, efforts and money in preliminary engineering designs.

Soil characteristics analysis based on the unified soil classification system

The purpose of this research is to determine soil classification and identify the swelling potential of soil clay in the Jababeka I (sample 1) and the Lippo Cikarang (sample 2), Indonesia. The research was carried out by the experimental method. Soil classification based on the Unified Soil Classification Systems (USCS) determined by No.200 sieve analysis and A-chart (LL vs PI chart), while based on the American Association of State Highway and Transportation Officials Soil Classification System (AASTHO), classification determined by No.200 sieve analysis, liquid limit (LL) and plasticity index (PI). The results show the soils are clay of high plasticity (CH) in determining of the USCS, whereas in AASTHO, the soils are A7-6, which means clay of high plasticity. Furthermore, the swelling potential or expansion potential of clay is determined by indirect methods namely by the results of LL, PI, SL, and percentage of the passing of sieve No.200. Moreover, consolidation test is also carried out to obtain compression coefficient (Cv) and coefficient of consolidation (Cc) to determine the mineral content. The results of this experimental research that soils contain kaolinite minerals, a very high swelling potential with the possible change in volume of 10-30 %.

Improvement of cement stabilized structural lateritic with pulverized snail shell

Abstract This study investigated the suitability of pulverized snail shell (PSS) as partial replacement of cement stabilized soil in foundation constructions. Preliminary and engineering tests were carried out on the soil samples. The optimum cement content fixed at 11% in correlation to Unified Soil Classification System, the PSS was introduced at varying percentages of 2%, 4%, 6%, 8% and 10%. Results revealed that, addition of PSS and 11% cement to lateritic soil caused a reduction in both liquid limits and plasticity index and an increased in plastic limits for all samples. Engineering tests showed the maximum dry density at optimum cement increased from 1493.34 ± 103.58 kg.m−3 to 1632 ± 435.81 kg.m−3 for sample A; 1476.77 ± 367.51 kg.m−3 to 1668 ± 202.58 kg.m−3 for sample B; 1460.77 ± 623.58 kg.m−3 to 1651 ± 135.45 kg.m−3 for sample C. The CBR recorded highest value at 4%PSS optimum cement for all samples. The addition of pulverized snail shell increased the strength of cement stabilized lateritic soil for structural foundation construction.

The Effect of Fines on Hydraulic Conductivity of Lawrencepur, Chenab and Ravi Sand

The amount of fines in sand greatly influence the permeability of sandy soils. Thus, this research was conducted to study the effect of plastic and non-plastic fines on the permeability of three types of sands (Lawrencepur sand, Chenab sand and Ravi sand). For this purpose, plastic and non-plastic fines were collected from different location of Lahore. Samples were prepared by mixing plastic and non-plastic fines into each type of sand separately, in amounts ranging from 0% to 50% with increments of five percent. Overall 63 samples were prepared. Sieve analysis and hydrometric analysis were performed to obtain particle size distribution for each sample. Atterberg’s limits were also determined and each sample was classified according to the Unified Soil Classification System (USCS). Compaction tests were performed on all samples as per the procedure in a standard Proctor test. The test samples were compacted in permeability molds with optimum moisture contents to obtain the density, as per a standard Proctor test. Hydraulic conductivity tests were performed on all sixty-three samples using a constant head permeameter and a falling head permeameter. Permeability results were plotted against the percentage of fines added. It was noted from the curves that the permeability of sand-fine mixtures shows a decreasing trend with the addition of fine contents. A few trials were performed to formulate a correlation. Validation of the correlation was performed with the results of 52 data sets from the field. Finally, the devised correlation was compared with three empirical equations proposed by Mujtaba, Kozeny–Carman and Hazen.

Stabilization of lateritic soil with cement – oil palm empty fruit bunch ash blend for California bearing ratio base course requirement

Lateritic soil obtained from a borrow pit at Maya Aladiye, Ijebu – Itokin Road, Ikorodu Local Government Area in Lagos state was classified as an A-6(8) using the American Association of State Highway and Transportation Officials (AASHTO) soil classification system or CL using the Unified Soil Classification System (USCS). It was treated with cement – oil palm empty fruit bunch ash (OPEFBA) blend in stepped concentrations of 0, 2, 4, 6 and 8 % cement as well as 0, 2, 4, 6 and 8 % of OPEFBA, respectively, by weight of dry soil. Index, cation exchange capacity (CEC), compaction and California bearing ratio (CBR) laboratory tests were carried out on the natural and treated soil specimens. Compaction was done using three different effort levels namely, the British Standard light (BSL), West African Standard (WAS) and the British Standard heavy (BSH). The 2-day CBR values (soaked) of the natural soil for the BSL, WAS and BSH compaction efforts increased from 10, 6 and 8 % to 105, 120 and 110 %, respectively, at an optimum 8 % Cement / 2 % OPEFBA treatment. These CBR values met the 80 % requirement for base course materials with a beneficial environmental advantage of utilizing a palm oil mill waste.

Improving the physical properties of clay using Sinabung volcanic and rice husk ash with UCT and CBR

Stabilization can be done by adding something to the soil in order to improve its strength and bearing capacity. One of the efforts to stabilize the soil is to add certain chemicals so that the soil will become solid. The additive materials used in this research are Rice Husk Ash (ASP) and Volcanic Ash (AGV) which is obtained from the eruption of Mt. Sinabung. The purpose of this research is to find index properties value as the effect of adding 2%, 4%, 6%, 8% Volcanic Ash and 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20% Rice Husk Ash on clay, to find the maximum compressive strenght value with UCT (Unconfined Compression Test), to find the CBR (California Bearing Ratio) value as the effect of adding the stabilization agents, and also to find the optimum content of adding Rice Husk Ash. According to the result of this research, the soil has 34.43% water content, 2.65 specific gravity, 47.33% liquid limit, 29.88% plasticity index, and 1.42 kg/cm2 compressive strength. Based on the classification system of Unified Soil Classification System (USCS), this soil is included in the group of CL which is inorganic clay with low to medium plasticity. Meanwhile based on the classification system of American Association of State Highway and Transportation Officials (AASHTO), this soil could be classified as type of soil A-7-6. The highest compressive strength value is obtained from the addition of 8% Sinabung ash and 2% Rice Husk Ash which is 3.17 kg/cm and the optimum CBR value also obtained from the addition of 8% Sinabung ash and 2% Rice Husk Ash which is 8.53%.

Critical state of compacted lateritic soil and palm kernel shell ash for earth embankments

For most treated soils in compacted form for earth embankments, interest had been limited to the maximum stresses they can sustain before failure. This work studied the stress–strain behaviour of a compacted lateritic soil treated with palm kernel shell ash (PKSA) from 0 to 18% at 3% intervals, with a major focus on the critical-state characteristics (beyond the maximum stresses). The lateritic soil was characterised as A-2-6(0) in the American Association of State Highway and Transportation Officials rating and clayey sand (SC) in the Unified Soil Classification System. The PKSA was found to be pozzolanic. The British Standard light energy level of compaction and drained shear test were carried out on the treated soil. The optimum moisture content increased while the maximum dry density reduced with an increase in PKSA content. The PKSA of 0–18% content by weight of the dry soil improved the strength properties of the lateritic soil by 51·43%. The critical-state parameters (λ, Γ and M) of the soil mixtures were found to be in conformity with the usual range for untreated soils.

PERBANDINGAN PENGGUNAAN SEMEN DAN GARAM UNTUK STABILISASI TANAH DASAR

Soil is the key of the road foundations. Soil of high CBR value will have good bearing capacity for road construction. Conversely, soil stabilization must be carried out to the subgrade that has bad bearing capacity. The goals of this analysis are to find out the soil characteristict of before stabilization, CBR values of before and after stabilization, the optimum cement use and salt (NaCl) use as stabilizers.The results of soil poperties test in Silt High Plasticity (MH) based on Unified Soil Classification System (USCS) and A-7-5 based on American Association of State Highway and Transportation Official (AASHTO). The result of CBR without stabilization is 3.64% for standard soaked and 5.13% for modified soaked. The maximum results of stabilized testing with cement showed 9.802 % CBR; 69.298% CBR of each sample respectively standard and modified soaked test; of salt showed 3.93% CBR; 5.33% CBR of standard and modified soaked test of each sample respectively. Keywords: CBR, cement, NaCl, soil stabilization

Modelling and comparing 3-D soil stratigraphy using subsurface borings and cone penetrometer tests in coastal Louisiana, USA

ABSTRACTComplex subsurface geology of coastal Louisiana, formed under fluvial, deltaic, and sea level influences, increases the uncertainty in design and construction of hard and natural infrastructure. In this study, twenty-four (24) collocated soil borings and CPTs at the Inner Harbor Navigation Canal (IHNC) in New Orleans, Louisiana were used to construct multiple three-dimensional (3-D) soil stratigraphy models by ordinary kriging. To explore the spatial distribution of soils at the site, four soil stratigraphy models were established, including the unified soil classification system (USCS) from borings and three constructed using soil behaviour type (SBT) correlations. The SBT correlation using friction ratio () and corrected cone resistance () was found to better represent organic soils pervasive in coastal Louisiana compared using normalised friction ratio with normalised cone resistance, and using soil classification boundary. The comparison shows that the normalisation of sleeve resistance translates the data to higher normalised friction ratio compared to values. The boring and CPTu sounding comparisons suggest that extending the from 8% to 20% in the Rf–qt chart to better capture the organic-rich soils in coastal Louisiana.

Lateritic Soil Treated with Waste Wood Ash As Liner in Landfill Construction

ABSTRACTInherent variability in engineering properties of lateritic soil in relation to its plasticity, permeability, strength, workability, and natural moisture content, has made it an unpredictable material for use in civil engineering works, resulting in the need for its treatment by stabilization. A lateritic soil classified as A-6(6) and CL, according to American Association of State Highway and Transportation Officials and Unified Soil Classification System of ASTM (2011), was treated with up to 10 percent waste wood ash (WWA). Compaction was carried out using four energies, namely, reduced British Standard light, British Standard light (BSL), West African Standard, and British Standard heavy, on samples, which were then examined for hydraulic conductivity, volumetric shrinkage, and unconfined compressive strength as major criteria for use as liner and for the development of acceptable zones. Specimens with 4 percent WWA content compacted with a minimum BSL energy satisfied the maximum hydraulic conductivity (k) value of 1 × 10−9 m/s, maximum volumetric shrinkage strain of 4 percent, and minimum unconfined compressive strength value of 200 kN/m2 required for use as liner in engineered landfills. The overall acceptable zone was enlarged for up to 4 percent WWA content, thereby accommodating higher moulding water content, but the minimum compactive effort required to achieve it became reduced. The beneficial treatment of lateritic soil with up to 4 percent WWA will perform satisfactorily as liner and covers in waste containment application and will minimize the pollution and environmental impact of wood waste disposal.

Microanalysis and Compactive Efforts Study of Black Cotton Soil Treated With Cement Kiln Dust

An expansive clay, also known as Black cotton soil (BCS) was treated with up to 10 % cement kiln dust (CKD) using three different compactive efforts; British Standard light (BSL), West African Standard (WAS) and British Standard heavy (BSH) energies. Laboratory tests were performed on the natural soil and CKD treated soil samples in accordance with BS 1377 (1990) and BS 1924 (1990) respectively with the aim of improving the deficient soil to meet engineering requirements. Preliminary evaluations on the natural black cotton soil showed that it fell under A-7-6 (16) using AASHTO classification and CL according to Unified Soil Classification System (USCS). Results of laboratory tests carried out on soil specimens show that the properties of the soil generally improved with CKD treatment. Peak unconfined compressive strength (UCS) values of 357.07, 382.49 and 528.82 kN/m2 and California bearing ratio (CBR) of 7, 10 and 19 % as well as resistance to loss in strength of 44, 55 and 55 % were recorded at 10 % CKD treatment, respectively, for BSL, WAS and BSH compactive energies. Reduction in the particle sizes with curing period was observed when samples were viewed through the scanning electron microscope (SEM). The study showed that CKD can be beneficially used to improve the subgrade of lightly trafficked roads and as admixture in lime stabilization during construction of flexible pavements over expansive soil.Keywords: California bearing ratio; Cement kiln dust, Durability; Expansive soil; Microanalysis, Unconfined compressive strength; Scanning electron microscope.

Pullout response of strengthened geosynthetic interacting with fine sand

This research describes results of pullout tests performed on two new systems to reinforce the fine-grained silica sand classified as SP in the Unified Soil Classification System. The first system is composed of geogrid on which transverse steel bars are tied to make a 3-D strengthened geogrid, here called Geogrid-Bar (GGB). In the second system, plastic push pins are attached to geocomposite and a strengthened geocomposite is made, here called Geocomposite-Pin (GCP). Eighteen pullout tests were conducted with the soil relative density of 80% revealed that the use of GGB and GCP systems causes the reinforcement pullout resistance to increase by about 37% and 46%, compared with normal planar geogrid and geocomposite, respectively.

Revisiting the CPT-based characterizations of a highway subgrade

ABSTRACTThis paper revisits the cone penetration test (CPT) based characterizations derived from small strain shear modulus (G0) and seismic shear wave velocity (Vs). The need for this study is demonstrated through comparisons with existing CPT-Vs/CPT – G0 models. Among the literary correlations considered in the present study, some of them showed better performance. The previous correlations show an error margin ranging between −140% and +440% in estimating the G0, whereas the predicted Vs was underestimated by 16% or overestimated by 109%. The CPT-G0 correlations utilizing the proposed compressibility index (Icc) denotes the higher regression coefficient value which designates the advantageous stress normalization. It is found that there is a good agreement between the measured and predicted Vs with expected error limits of ± 4%. Moreover, the proposed correlations in this study might be applicable to site-specific conditions due to the limitation of data points pertinent to organic silts and clays category based on the unified soil classification system.

Stabilization of Lateritic Soil Using Coir Fiber as Natural Reinforcement

Stabilization of soil using fibers is one of the effective techniques to improve the strength of soils for engineering se. This paper aims to evaluate the effect of coir fiber as natural reinforcement in the stabilization of lateritic soil, which is classified as clayey silt. The performance of Coir fibers is separately analyzed for its impact on the strength of the soil. Tests were conducted on various fiber-soil ratios in six percentage levels such as 0, 0.2, 0.4, 0.6, 0.8 and 1.0 to determine the optimum fiber content. The index properties tests carried out on the natural soil samples (A and B) showed that the samples belong to A-6 and A-7-6 in the AASHTO classification system respectively and CL according to the Unified Soil Classification System (USCS). Compaction characteristics of the natural and treated soil samples were determined using the Standard Proctor method. Unconfined compressive strength (UCS) value of 58.59kpa and 87.89kpa obtained for the natural soil, increased to a maximum of 359.31kpa and 261.16kpa at 0.4% fiber content for samples A and B respectively. The California bearing ratio (CBR) values on the other hand increased with increase in fiber content from 14.52% to 23.28% and from 12.47% to 18.92% for soaked samples A and B respectively, and from 17.26% to 27.18% and 15.22% to 21.89% for unsoaked samples A and B respectively. The results indicate that, 0.4% coir fiber content are more optimal and efficient stabilizer for the laterite soil. This study also contributes to effective soil waste management as a befitting sustainable technique to solve current environmental crisis as well.

Effect of Saturation Levels on Shear Strength and Bearing Capacity Properties of Soil Types

This study presents a comprehensive set of laboratory works for the examined soil layers extracted from Baghdad city (specifically from Alkadhimya, Alaitaifiya, and Alhurriya) to illustrate their engineering properties. The researchers have adopted the unified soil classification system for soil classification purposes. Also, the direct shear test was performed for soil samples with various degrees of saturation (0%, 25%, 50%, 75%, and 100%). The test results have shown a significant reduction in cohesion property with higher moisture content within soil samples. Also, a noticeable reduction in angle of internal friction value has occurred with such changes. Furthermore, it has been found that the bearing capacity of unsaturated soils ranged between 2000 and 3000 KPa, and about 500-700 KPa for the soaked soil samples.

SUITABILITY OF RICE HUSK ASH TREATED BLACK COTTON SOIL FOR WASTE CONTAINMENT APPLICATION

This paper presents an experimental study aimed at assessing the suitability of rice husk ash (RHA) treated black cotton soil as a barrier in Municipal Solid Waste (MSW) containment facility. Laboratory tests were conducted on black cotton soil treated with 5, 10 and 15% RHA at moulding water contents of 2 and 4% on both wet and dry sides of optimum moisture content (OMC) using British Standard Heavy (BSH) compactive effort. Index properties, hydraulic conductivity (k), volumetric shrinkage strain (VSS), and unconfined compressive strength (UCS) tests were conducted on all the samples. The results obtained indicated that the soil was classified as A-7-5(18) according to the American Association of States Highway and Transport Officials (AASHTO) classification system and Silt of high plasticity (MH) in accordance with the Unified Soil Classification System (USCS). It was observed that addition of RHA was accompanied with decrease in the plasticity index from 24 to as low as 3%. An improvement in the moisture-density relationship of the soils showed an increase in Maximum Dry Density (MDD) from 1.46 to 1.52 Mg/m3 as well as a decrease from 24.5 to 21.2% in OMC. The increase in RHA contents up to 10% brought about an improvement in the strength of the soil specimens by almost 332.4kN/m2 at 2% on the dry side of OMC. The VSS decreases with increase in RHA content to achieve the minimum shrinkage strain of 4.1% at 5% RHA treatment.

SUITABILITY OF RICE HUSK ASH TREATED BLACK COTTON SOIL FOR WASTE CONTAINMENT APPLICATION

This paper presents an experimental study aimed at assessing the suitability of rice husk ash (RHA) treated black cotton soil as a barrier in Municipal Solid Waste (MSW) containment facility. Laboratory tests were conducted on black cotton soil treated with 5, 10 and 15% RHA at moulding water contents of 2 and 4% on both wet and dry sides of optimum moisture content (OMC) using British Standard Heavy (BSH) compactive effort. Index properties, hydraulic conductivity (k), volumetric shrinkage strain (VSS), and unconfined compressive strength (UCS) tests were conducted on all the samples. The results obtained indicated that the soil was classified as A-7-5(18) according to the American Association of States Highway and Transport Officials (AASHTO) classification system and Silt of high plasticity (MH) in accordance with the Unified Soil Classification System (USCS). It was observed that addition of RHA was accompanied with decrease in the plasticity index from 24 to as low as 3%. An improvement in the moisture-density relationship of the soils showed an increase in Maximum Dry Density (MDD) from 1.46 to 1.52 Mg/m3 as well as a decrease from 24.5 to 21.2% in OMC. The increase in RHA contents up to 10% brought about an improvement in the strength of the soil specimens by almost 332.4kN/m2 at 2% on the dry side of OMC. The VSS decreases with increase in RHA content to achieve the minimum shrinkage strain of 4.1% at 5% RHA treatment.

Effect of rice husk ash admixed with treated sisal fibre on properties of lateritic soil as a road construction material

The effect of rice husk ash admixed with treated sisal fibre on properties of lateritic soil as a road construction material was studied. The natural soil falls under A-7-6(10) classification using the American Association of State Highway and Transportation Officials (AASHTO) classification and CL (Lean Clay) according to Unified Soil Classification System (USCS). Treatment of the soil was done with Rice Husk Ash (RHA) and treated Sisal Fibre (SF) in stepped concentrations of 0, 2, 4, 6, 8% and 0, 0.25, 0.5, 0.75, 1.0% by dry weight of soil, respectively. Preliminary test, compaction test (using British Standard light (BSL) energy) and unconfined compressive strength (UCS) test were carried out. Analysis of variance was carried out using Microsoft Excel Analysis Tool Pak Software Package. Mini-tab R15 Software was used for regression analysis. Laboratory results were used to generate reliability indices using a FORTRAN based first order reliability program. Outcome of the laboratory tests show that MDD decreased from 1.85 mg/m3 for the natural soil to 1.73 mg/m3 at 0% RHA/1% SF content. The OMC increased from 18% for the natural soil to 26.5% at 6% RHA/1% SF content. The UCS increased from 100.57 kN/m2 for the natural soil to 139.38 kN/m2 at 0% RHA/0.25%SF content by dry weight of soil. The increasing trend continued to 696.63 kN/m2 at optimum 6% RHA/0.75%SF content by dry weight of soil, which met the regulatory minimum UCS value of 687–1373 kN/m2 for pavement applications. Reliability indices varied for all the variables considered with MDD and OMC having more significant effect on the UCS. Based on the results obtained, an optimum blend of 6%RHA/0.75% SF content by dry weight of soil is recommended for used as sub-based material for lightly trafficked roads.

Evaluation of compaction parameters of fine-grained soils using standard and modified efforts

Compaction characteristics of the soil have the great importance for practically achieving the desired strength, permeability and compressibility of soil during the construction. Standard compaction test (SCT) and modified compaction test (MCT) are two very famous laboratory test methods to determine the compaction characteristics of soils worldwide. Modest efforts have been made in the past to correlate the compaction parameters drawn from these two tests with each other. In the present study, authors are established the models to predict the modified compaction parameters (γdmax(m) and wopt(m)) by using standard compaction parameters (γdmax(s) and wopt(s)) or vice versa for the fine-grained soils. Such models can extricate from performing additional tedious and laborious compaction tests. Moreover, the effect of plasticity on the compaction parameters obtained using standard and modified effort is also discussed. Total 156 disturbed fine-grained soil samples were collected from different areas of Pakistan. The index properties tests and laboratory compaction tests were performed using these soil samples. On the basis of index properties tests, these soil samples were classified into different sub-groups of fine-grained soil as per the Unified Soil Classification System. Relationships between the plasticity index (IP) and compaction parameters of both MCT and SCT were also accomplished. Out of 156 soil samples, test results of 126 samples are used to develop the correlations and test results data of 30 samples was used to validate the developed correlations. The percentage error in the correlation between γdmax(m) and γdmax(s) is observed to be only ± 0.4% and for the correlation between wopt(m) and wopt(s) the percentage error is observed to be ± 2.7%.