Granite Residual Soil Research Articles

CIRI-CIRI KEJURUTERAAN TANAH BAKI GRANIT DI SEMENANJUNG MALAYSIA

Pengetahuan tentang kelakuan dan korelasi antara ciri-ciri tanah adalah penting dan berguna bagi rekabentuk dan ramalan pembinaan. Objektif utama kajian ini adalah untuk menentukan sifat-sifat kejuruteraan tanah baki granit di Semenanjung Malaysia. Tanah baki granit di Semenanjung Malaysia boleh dikelaskan sebagai tanah liat hingga pasir berkelodak dengan keplastikan rendah sehingga tinggi. Kandungan lembapan semulajadi bertambah dengan kedalaman dan kandungan lempung dan ianya berjulat di antara 10% - 40 %. Nilai graviti tentu didapati berjulat di antara 2.50 dan 2.74. Indeks mampatan, pekali pengukuhan dan pekali kebolehtelapan masing-masing berjulat 0.11– 0.42, 1.53 – 49.64 m2 tahun-1 dan 1.1 x – 9.86 x 10-9 ms-1. Nilai kejeleketan berkesan pula antara 0 – 36.4 kNm-2 manakala sudut geseran berkesan di antara 16º – 31º. Beberapa kolerasi di antara ciri-ciri kejuruteraan tanah baki dapat ditentukan dan boleh dijadikan panduan dalam rekabentuk awalan bagi pembinaan struktur

Influence of drying–wetting cycles on soil-water characteristic curve of undisturbed granite residual soils and microstructure mechanism by nuclear magnetic resonance (NMR) spin-spin relaxation time (T2) relaxometry

Due to the formational environment and climatic variability, granite residual soils with grain-size distribution ranging from gravel to clay undergo multiple drying–wetting cycles. The influences of multiple drying–wetting cycles on the soil-water characteristic curve (SWCC) and pore-size distribution (POSD) of undisturbed granite residual soils are investigated using the pressure plate test and nuclear magnetic resonance (NMR) spin-spin relaxation time (T2) distribution measurement, respectively. Results show that the water-retention capacity and air-entry value decrease and pores become more uniform with increasing drying–wetting cycles. After four drying–wetting cycles, the soil reaches a nearly constant state. The POSD change of multiple drying–wetting cycle samples is consistent with the SWCC of the soils. Furthermore, a modified van Genuchten model in terms of cumulative pore volume is used to obtain the best-fit POSD of the drying–wetting cycle samples. The shape and changing tendency of both curves of SWCC and POSD are quite similar and achieved a better correlation. It can be concluded that the SWCC is strongly dependent on the POSD of the soil and NMR T2relaxometry can be used as an alternative to the assessment of microstructural variation of residual soils subjected to the periodic drying and wetting process.

Characteristics of Gravelly Granite Residual Soil in Bored Pile Design: An In Situ Test in Shenzhen

Granite residual soil is widely distributed in south China and is treated as a special soil. Its design parameters in rotary drilling bored piles are a matter of debate due to lack of in‐situ pile load tests. Back‐analysis of test piles is a reliable means of studying the geotechnical capacity of granite residual soil for pile design. In this study, a series of in situ tests was conducted comprising six full‐scale instrumented test piles in gravelly granite residual soil in Shenzhen to consider the effects of different construction methods. The six piles were constructed with three different rotary drilling methods. Two commonly used design methods were investigated in the back‐analysis: the SPT and effective stress methods. The results of the loading tests and strain gauges were used to obtain the back‐analyzed parameters of the ultimate shaft resistance and ultimate base resistance for gravelly granite residual soil with these two design methods.

Anchored Retaining Walls in Granite Residual Soils I – Parametric Study

Anchored Retaining Walls in Granite Residual Soils I – Parametric Study

Anchored Retaining Walls in Granite Residual Soils II. A Method for Preliminary Design

Anchored Retaining Walls in Granite Residual Soils II. A Method for Preliminary Design

Uncertainty of the Soil–Water Characteristic Curve and Its Effects on Slope Seepage and Stability Analysis under Conditions of Rainfall Using the Markov Chain Monte Carlo Method

It is important to determine the soil–water characteristic curve (SWCC) for analyzing slope seepage and stability under the conditions of rainfall. However, SWCCs exhibit high uncertainty because of complex influencing factors, which has not been previously considered in slope seepage and stability analysis under conditions of rainfall. This study aimed to evaluate the uncertainty of the SWCC and its effects on the seepage and stability analysis of an unsaturated soil slope under conditions of rainfall. The SWCC model parameters were treated as random variables. An uncertainty evaluation of the parameters was conducted based on the Bayesian approach and the Markov chain Monte Carlo (MCMC) method. Observed data from granite residual soil were used to test the uncertainty of the SWCC. Then, different confidence intervals for the model parameters of the SWCC were constructed. The slope seepage and stability analysis under conditions of rainfall with the SWCC of different confidence intervals was investigated using finite element software (SEEP/W and SLOPE/W). The results demonstrated that SWCC uncertainty had significant effects on slope seepage and stability. In general, the larger the percentile value, the greater the reduction of negative pore-water pressure in the soil layer and the lower the safety factor of the slope. Uncertainties in the model parameters of the SWCC can lead to obvious errors in predicted pore-water pressure profiles and the estimated safety factor of the slope under conditions of rainfall.

Adsorption Study on Mixture Material of Granite Residual Soil – Palm Oil Fuel Ash (POFA)

Granite residual soil mixed with up to of palm oil fuel ash POFA by dry weight was investigated to ascertain its adsorption capacity with regards to its use as an adsorbent material for leachate A batch equilibrium adsorption study was carried out in which the effect of dosage and pH on the adsorption capacity of granite residual soil ndash POFA mixture was determined In general the results showed that adsorbent dosage and pH had significant effect on the sorption capacity of the soil ndash POFA mixture Such as example Manganese ion which had the highest initial concentration of mg l in leachate once gone through the shaking process the amount which had been adsorbed by the admixture increased from mg g at POFA content to mg g at POFA The increased pattern of adsorption capacity of the admixtures occurred with the increment of pH values The optimum condition for the effectiveness sorption of contaminant for the mixture is POFA content and pH values is It can be concluded that the mixture granite residual soil ndash POFA is expected to be an economical adsorbent product for metal ion remediation in leachate

Durability Improvement of Granite Residual Soil by Lime

Granite residual soil is a kind of common building material for subgrade in China. However, its stability and durability are not as good as requested by specification. Lime is regarded as an effective modifier for granite residual soil. The influence of lime dosages on stability and durability of granite residual soil are evaluated and its effectiveness is verified and quantified based on lab tests of modulus and strength. It is shown that the performance improvement is obvious. Modified granite residual soil has better support to pavement structure and improves the stability and durability of pavement.

Measuring Hydraulic Conductivity Using Geotechnical Centrifuge

This study investigated the validity of hydraulic conductivity value using Mini Column Infiltration Test. Granitic residual soils from Broga Selangor, Malaysia were tested to obtain the hydraulic conductivity value in relatively shorter time. Soil samples were physically characterized before being tested using Centrifuge Mini Column Infiltration Technique. A normal 1-g Falling Head Permeability Test (Kf) was also being performed as a comparison with hydraulic conductivity value from Centrifuge Test (Kcen). For centrifuge test (Kcen), there were three factors involved; rotation speed, soil thickness and type of solution (single or mixture solution). Hydraulic conductivity value from Centrifuge Test (Kcen) also was highly depending on the Scale Factor Value (SFV). The results from Centrifuge Test showed that the higher rotation speed, the lower SFV would be. Hydraulic conductivity was decreasing with an increasing of rotation speed. The increment of soil thickness also contributed to the decrement of SFV and hydraulic conductivity value. Thus, the hydraulic conductivity value would be more accurate when higher rotation speed and higher soil thickness were applied. Hydraulic conductivity, Kcen for a single solution also showed higher values compared to mixture solutions. However, some of hydraulic conductivity value (Kcen) showed overestimated values due to the presence of cracks in the soil (mudcakes). Most of the scale factors gave low values (x<1.00) which meant x values were close to unity. The value of hydraulic conductivity for 1-g Permeability Test (Kf) was 2.08×10-6 m/s. While for 10mm soil thickness and 2500 RPM (1440 -g) velocity of a single solution, the value of hydraulic conductivity (Kcen) was 6.82×10-4 m/s. Since the scale factor obtained was less than 1 (x = 0.74), the value of Kcen could be used as a valid number to replace the value of Kf from 1-g Permeability Test. This study concluded that by using scale factor, the relationship between HCV from Centrifuge Tests and Falling Head Permeability Tests could be known; thus, Centrifuge modeling could be developed as a valid method in determining the hydraulic conductivity of the soils.

Hydraulic Conductivity of Compacted Granite Residual Soil Mixed with Palm Oil Fuel Ash in Landfill Application

Laboratory tests were carried out on compacted granite residual soil treated with 0 to 15% Palm Oil Fuel Ash (POFA), with a view to evaluate its hydraulic conductivity for its application in landfilling. The Soil–POFA mixtures were compacted using both Standard and Modified Proctors compactive efforts at 2% dry of Optimum Moulding water Content (−2%), at Optimum Moulding water Content (0%), at 2 and 4% on the wet side of Optimum Moulding water Content (+2 and +4%). The samples were permeated with water and the effect of moulding water content; compactive effort and POFA content were examined. The samples that met the minimum threshold of 1 × 10−9 m/s were used in plotting the acceptable zones criterion at various POFA mixtures. The results gave indications of reduction in the hydraulic conductivity values, with increase in compactive efforts, moulding water content and POFA content up to about 10%. This was the most suitable soil–POFA mixture for the hydraulic application.

EXPERIMENTAL STUDY ON NONLINEAR SHEAR STRENGTH BEHAVIOR OF A TROPICAL GRANITIC RESIDUAL SOIL (GRADE VI) AT VARIOUS INITIAL MOISTURE CONTENTS

The conventional theories of soil mechanics use linear envelope to derive shear strength; this however, leads to an overestimation of the factor of safety in the examination of slopes. Therefore, the incorporation of methods that acknowledge the existence of non-linear characteristics of shear strength is necessary in the analysis of slopes specifically. This is due to the substantial influence of non-linear shear strength behavior on the slope failure mechanism when they are at low stress levels. In this paper, the nonlinearity of shear strength for grade VI granitic residual soil is studied. “Non-Axis Translation Consolidated Drained Triaxial” tests were performed at various ranges of net stress and suction. Thereafter, to characterize shear strength behavior, shear strength parameters were derived. The soil-water characteristic curve was plotted after conducting “Pressure Plate Extractor” test at a series of suction. The result substantiated the non-linearity of shear strength for granitic residual soil based on net stress and suction.

石灰与水泥改性花岗岩残积土耐久性的对比评价

花岗岩残积土粘聚力小，水稳定性差，遇水易崩解，应用时需进行土体改性。其中在土体中掺入水泥或石灰是最常用的化学改性方式。展开室内试验，分别将石灰及水泥掺入花岗岩残积土进行土体改性，从CBR强度、崩解特性和水稳性三个方面对比评价石灰与水泥改性花岗岩残积土耐久性。结果表明，在最佳掺加量下，水泥改性后的各项指标基本均优于石灰改性，水泥改性花岗岩残积土的耐久性更优。 Granite residual soil has little cohesive force and poor water stability. It is easy to disintegrate in water, and soil modification is needed in application. The incorporation of cement or lime in the soil is the most commonly used chemical modification. The lime and cement were mixed into granite residual soil for soil modification, and the durability of lime and cement modified granite residual soil was evaluated from CBR strength, disintegration characteristics and water stability. The results show that under the optimal dosage, the indexes of cement modification are better than lime modification, and the durability of cement-modified granite residual soil is better.

花岗岩残积土压实效果影响因素评价与分析

花岗岩残积土分布广泛，但变异性大、卸荷崩解、遇水软化和高液限，压实特性不易控制。本文从研究土体基本性质出发，结合工程中压实及检测方法存在的问题，分析影响压实效果的因素。选取砂类残积土路基、改良土路基和土石混填路基三段试验路进行现场振动压实试验，通过振动信号测试和原位压实质量测试，将处理分析的结果与通过测定压实度反应压实质量的传统方法进行对比。研究结果表明，幅值法(AA)和谐波比值法(CMV, CCV)可以作为压实质量连续检测的有效方法。 Granite residual soil is widely distributed, but it has large variability and high liquid limit, and it disintegrated after unloading, softened with water, causing that its compaction characteristic is difficult to control. This paper based on the study of the basic properties of soils, combining the problems of compaction and testing methods of the actual project, analyzing the factors that affect the compaction effect. Three kinds of the test road which include sand-based residual soil subgrade, improved soil subgrade and soil-filled roadbed were selected to carry on on-site vibration compaction test. Through the vibration signal test and in-situ compaction quality test, the results of the analysis were compared with the traditional method of the compaction quality by testing compactness. The results show that the amplitude method (AA) and harmonic ratio method (CMV, CCV) can be used as an effective method for continuous testing of compaction quality.

ATTENUATION CAPACITY OF SOIL MIXED WITH PALM OIL FUEL ASH (POFA) LINER FOR TREATING LEACHATE

This paper presents the results of a study on the effectiveness of mixtures of granite residual soil with palm oil fuel ash (POFA) to attenuate leachate contaminants. Granite residual soil samples were mixed with 0 to 15% POFA. A short term filtration processes and hydraulic conductivity test were conducted simultaneously using a falling head apparatus with natural leachate as the permeant. The values of natural attenuation capacity of the compacted soil mixed with various percentage of POFA were determine by carrying out several water quality tests on the influent and effluent. The parameters measured were Total Suspended Solids (TSS), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) values and some selected heavy metal (Chromium, Copper, Manganese, Lead and Zinc). The results showed the highest reduction in hydraulic conductivity (65.4%) was achieved by the compacted soil mixed with 10% POFA. The removal rate of all parameters studied except for copper increased with the increment of POFA content

Slope Stability Assessment and Evaluation of Remedial Measures Using Limit Equilibrium and Finite Element Approaches

Slope stability is a recurrent theme amongst all branches of civil engineering and is of major significance on large scale infrastructure projects such as highways, railways or canals, where having more cost effective designs becomes a crucial drive on any scheme. The aim of this paper is to numerically back-analyse the stability of an existing experimental embankment built under the supervision of PhD students at UBI, making use of one of the region's most abundant resource, its granitic residual soil, very commonly used in road schemes. This is part of an on-going study of this natural resource, which has begun by undertaking a laboratory geotechnical characterisation of the granitic residual soil in question.To better understand the potential of the residual soil, this paper is primarily focused on the determination of the Margins of Safety using different calculation methods (LEM and FEM), to allow for an expedite assessment of the stability of granitic residual soil slopes, for different soil properties, geometries, applied loads and groundwater conditions. Additionally, this paper also tries to quantify the merits of some of the most common remediation techniques, drawing a comparison between their effectiveness. However, the remedial options discussed and analysed should be perceived as concept ideas as their gain in terms of MoS will likely vary from case to case. Furthermore, the benefits of combining the effects of more than one remedial options has been excluded from this study.The parametric study has made use of one LEM based software (SLOPE/W) and one FEM based software (PLAXIS 2D), which have allowed for some conclusions to be drawn for each set of conditions, in particular due to changes in groundwater levels and applied surcharges at the crest.

Cyclic and Post-cyclic Shear Behaviour of a Granite Residual Soil – Geogrid Interface

The dynamic frictional properties of the soil-geosynthetic interface play an important role in the design and stability analysis of geosynthetic-reinforced soil structures under repeated loadings, such as those induced by compaction, traffic and earthquakes. This paper describes a laboratory study carried out using a large-scale direct shear test device, aiming to investigate the cyclic and post-cyclic behaviour of an interface between a granite residual soil and a biaxial woven geogrid. In the cyclic direct shear tests, the interface was subjected to 40 cycles of sinusoidal displacement, with semi-amplitude and frequency ranging from 1-10 mm and 0.05-0.5 Hz, respectively. To evaluate the effect of the cyclic loading on the interface shear strength, monotonic direct shear tests were performed immediately following the cyclic tests. The results indicated that the loading frequency has little impact on the interface shear stiffness during the loading cycles. In contrast, the influence of the displacement semi-amplitude on the interface stiffness was found to be significant. The cyclic loading did not lead to the degradation of the post-cyclic interface shear strength. The post-cyclic peak shear strength tended to increase with the semi-amplitude of the shear displacement, which may be associated with an increase in soil density.

Stress-Strain response of Malaysian granitic residual soil grade V, according to Rotational Multiple Yield Surface Framework

In soil mechanics characterizing the soil volume change behavior is based on the effective stress concept. Conventional soil settlement models which have been developed by this principle, are empirical in nature and being verified against experimental or field observations. However, they are not still able to explain and formulate some unusual soil volume change behaviors such as wetting collapse by this concept. The consequence of shear strength in the interaction of effective stress should be integrated into volume change frameworks in such cases in order to puzzle out these weird behaviors. The principle has been incorporated in an anisotropic soil settlement model know as Rotational Multiple Yield Surface Framework (RMYSF). The framework has been developed from the standpoint of the soil stress-strain response within anisotropic stress condition. The anisotropic soil volume change behavior is described from the interaction between applied stress (presented by the Mohr-Coulomb circle) and shear strength (in terms of curved-surface mobilized shear strength envelope). The applicability of the model has been examined for limestone gravel from the United Kingdom and granitic residual soil grade VI from Kuala Kuba Baru, Malaysia before, however still needs to be tested for another kind of soils. In this paper, a series of triaxial tests were conducted on Malaysian granitic residual soil grade V, in saturated and unsaturated condition. The stress-strain curves and volume change behavior of the soil were obtained from laboratory test results. Besides that, the stress-strain response of the soil has been predicted using RMYSF framework. The predicted stress-strain curves were compared with the test result and the accuracy of the framework was examined. The obtained and predicted curves had a fairly good match.

INSTRUMENTED PILE LOAD TESTING WITH DISTRIBUTED OPTICAL FIBRE STRAIN SENSOR

An instrumented pile load test was conducted for a 1.2m diameter bored pile at Putrajaya to verify pile performance towards geotechnical design. This test pile was instrumented with new monitoring technique using distributed strain sensing known as Brillouin Optical Time Domain Analysis (BOTDA) and compared with conventional sensors, i.e. vibrating wire strain gauge, LVDT (linear variable differential transformer) and dial gauge. This manuscript includes the description of subsurface conditions consisting of weathered granitic residual soils, test pile installation and instrumentation setup of Maintain Load Test (MLT). Field measurement results such as the load transfer response and average unit shaft resistance using the distributed fibre optic strain sensor were well matched with the results using the conventional sensors. However, the distributed fibre optic strain sensor has the added advantage of detecting the localized defect such as pile necking, bending, and overall behaviour of bored pile effectively.

Experimental investigation on the pullout behaviour of geosynthetics embedded in a granite residual soil

Geosynthetics, including geogrids and geotextiles, have been extensively used for stabilisation and soil reinforcement in several geotechnical structures, such as foundations, abutments, walls and slopes. In these applications, soil–geosynthetic interaction plays a determinant role. This paper describes an experimental study carried out using a large-scale pullout test apparatus, aiming to investigate the pullout behaviour of different geosynthetics embedded in a granite residual soil. The study involved two geogrids (one biaxial and the other uniaxial), one geocomposite reinforcement (high-strength geotextile) and one geotextile. The soil was compacted to different relative densities. Test results have revealed that soil–geosynthetic interaction under pullout loading conditions is highly influenced by the geosynthetic properties and soil density. Regardless of soil density, the biaxial geogrid exhibited higher pullout resistance than the other geosynthetics. At maximum pullout force, the deformation along the length of the geotextiles was considerably more pronounced than that along the geogrids. For the conditions adopted in this study, the soil–geosynthetic pullout interaction coefficients ranged from .25 to .52. In general, the values of the scale effect correction factor obtained for the geotextiles were slightly lower than the value recommended by the Federal Highway Administration in the absence of test data.

Direct shear behaviour of residual soil–geosynthetic interfaces – influence of soil moisture content, soil density and geosynthetic type

ABSTRACT: Soil–geosynthetic interface shear strength is an essential parameter for the design and stability analysis of geosynthetic-reinforced soil structures. Economic and environmental reasons have led to increasing use of locally available residual soils with a significant percentage of fines and lower draining capacity, when compared with the traditional good-quality backfill materials. This paper describes an extensive laboratory study carried out using a large-scale direct shear test device, in which the influence of soil moisture content, soil density and geosynthetic type on the direct shear behaviour of the soil–geosynthetic interface was evaluated. The study involved a locally available granite residual soil and four geosynthetics: two geogrids (one uniaxial and the other biaxial), one geocomposite reinforcement (high-strength geotextile) and one geotextile. Test results have revealed that the increase in soil moisture content can measurably reduce the soil–geosynthetic interface shear strength. Regardless of soil moisture content, soil density proved to have a remarkable influence on interface shear strength, particularly when geogrids were used. Among the different geosynthetics tested, the biaxial geogrid was found to be the most effective reinforcement for this particular type of soil, concerning the direct shear mechanism. For soil–geogrid interfaces, the coefficients of interaction ranged from 0.71 to 0.99. For soil–geotextile interfaces, the coefficients of interaction varied from 0.54 to 0.85.