scholarly journals Settlement Analysis of Treated Soft Clay using LECA Replacement through Numerical Modelling

CONSTRUCTION ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 76-84
Author(s):  
Azhani Zukri
Keyword(s):  
Internal Friction ◽  
Soft Soil ◽  
Soft Clay ◽  
Friction Angle ◽  
Shallow Foundations ◽  
Internal Friction Angle ◽  
Filling Material ◽  
Settlement Prediction ◽  
Replacement Technique ◽  
Settlement Analysis

Soil replacement technique is the simplest and oldest way in improving the soft soil under the shallow foundations. The process started by taking or removing the un-wanted problematic part of soils and replacing it with other efficient materials. Therefore, this study conducted to analyse on the soft soil replacement using Lightweight Expanded Clay Aggregate (LECA) as a filling material instead of common aggregate. LECA has been widely used in geotechnical application as the materials were successfully recognized in minimising the dead loads by more than half. The settlement magnitude of treated soft soil with LECA replacement was analysed through finite element method by using PLAXIS 2D commercial software. The prediction graph for various internal friction angle has been developed for settlement estimation The graph was then validated using developed Settlement Prediction Model, analytical equations, and numerical analysis. Another finding from this study is a decrease in the magnitude of the settlement as the internal friction angle of LECA increases.

An Experimental Study on the Mechanical Characteristics of Sandstone-Like Material with Preset Filling Joints

2013 ◽  
Vol 353-356 ◽  
pp. 644-649
Author(s):  
Xin Yu Liu ◽  
Ai Hua Liu ◽  
Bang Biao Wu
Keyword(s):  
Internal Friction ◽  
Uniaxial Compression ◽  
Shear Failure ◽  
Experimental Studies ◽  
Deformation Modulus ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Filling Material ◽  
Shear Tests ◽  
Intact Specimen

This paper investigates the strength and deformation characteristics of the sandstone-like material containing the preset filling joints. The test specimens are designed with different height-diameter ratio. The uniaxial compression and shear tests were performed during the experimental studies. The results show that: (1) the failure models of the 3 kinds specimens including ones without joints, ones with "cruciform" joints and ones with "intersecting parallels" joints are similar to the general trend, e.g. X-shaped conjugated single-slope shear failure and single-slope shear failure under compression and shear tests ; (2) under uniaxial compression, the performance of intact specimen is clearly affected by its size, and the strength of jointed one is significantly affected by the weakening of the structure. This impact depends on the joints conditions, e.g. joint density, with filling material or without filling material; (3) Deformation modulus E and Cohesion c have no significant change for the 2 kinds jointed specimens, but the internal friction angle is obviously affected by joints and their fillings. The internal friction angle decreases rapidly with the increase of joints number.

Experimental Study on Structural Properties Influencing on Shear Strength of Soft Clay

2011 ◽  
Vol 243-249 ◽  
pp. 2487-2490
Author(s):  
Jiang Feng Wang ◽  
Yong Le Li ◽  
Yan Bin Gao ◽  
Yong Xiang Yang
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Shear Failure ◽  
Clayey Soil ◽  
Soft Clay ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Undisturbed Soil ◽  
Direct Shear Tests ◽  
Reconstituted Soil

The direct shear tests were conducted with undisturbed and reconstituted soft clay, then the structural influence on shear strength was studied, and the laws were got. No matter shear strength of slow shear or consolidated quick shear on undisturbed and reconstituted soil have not peak values, strength line of reconstituted soil is a slash, but the shear strength line of undisturbed soil is obviously a broken line. The internal friction angle of undisturbed and reconstituted soil is basically the same. There are good linear relationship between internal friction angle and plastic index of clayey soil. The amplitude of internal friction angle of reconstituted soil decreasing with plastic index increasing is less than that of undisturbed soil. From wf-lgp curve can be seen, with the increasing of vertical stress, water content of shear failure decrease gradually, and linear correlation of each curve is very good.

Determine the Shear Strength of Aeolian Sand and Bearing Capacity

2014 ◽  
Vol 580-583 ◽  
pp. 165-168
Author(s):  
Ying Zi Yin ◽  
Ya Lei Wang
Keyword(s):  
Internal Friction ◽  
Moisture Content ◽  
Bearing Capacity ◽  
Retaining Wall ◽  
Friction Angle ◽  
Optimum Moisture Content ◽  
Internal Friction Angle ◽  
Dry Density ◽  
Filling Material ◽  
Aeolian Sand

In this article, through aeolian sand sample study in Inner Mongolia Baotou area, to determine the aeolian sand maximum dry density and optimum moisture content. On this basis, the aeolian sand cohesion and internal friction angle were measured by the quick direct shear test when aeolian sand was at the optimum moisture content and near the most largest compactness. And the bearing capacity of retaining wall model which regarded aeolian sand as fillers was determined. Then bearing capacity change of aeolian sand wrapped before and after was compared. Experimental results showed that: when the aeolian sand was in the wet and compacted state, its cohesion was 3.31 kPa and internal friction angle was 36.8°. The aeolian sand bearing capacity was 153.8kPa by the plate loading test. The aeolian sand wrapped with a geotextile bearing capacity was 194.1kPa. Through the aeolian sand research of Baotou area, it provides a useful reference for the construction of highway and railway and application of wrap-reinforced retaining wall which is a new retaining structure in the region, and the aeolian sand is treated as a special filling material in these structures.  

Characterization of Shear Strength and Interface Friction of Organic Soil

2020 ◽  
Vol 857 ◽  
pp. 203-211
Author(s):  
Majid Hamed ◽  
Waleed S. Sidik ◽  
Hanifi Canakci ◽  
Fatih Celik ◽  
Romel N. Georgees
Keyword(s):  
Shear Stress ◽  
Shear Strength ◽  
Internal Friction ◽  
Moisture Content ◽  
Water Content ◽  
Friction Angle ◽  
Structural Materials ◽  
Organic Soil ◽  
Internal Friction Angle ◽  
Interface Friction

This study was undertaken to investigate some specific problems that limit a safe design and construction of structures on problematic soils. An experimental study was carried out to examine the influence of loading rate and moisture content on shear strength of organic soil. Influece of moisture content on interface friction between organic soil and structural materials was also attempted. A commonly used soil in Iraq was prepared at varying moisture contents of 39%, 57% and 75%. The experimental results showed that the increase in water content will decrease the shear stress and the internal friction angle. An increase of the shearing rate was found to decrease the shear stress and internal friction angle for all percetanges of water contents. Further, direct shear tests were carried out to detect the interface shear stress behavior between organic soil and structural materials. The results revealed that the increase in water content was shown to have significant negetavie effects on the interface internal friction and angle shear strength.

scholarly journals Influence of Structural Plane Microscopic Parameters on Direct Shear Strength

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yanhui Cheng ◽  
Weijun Yang ◽  
Dongliang He
Keyword(s):  
Particle Size ◽  
Shear Strength ◽  
Internal Friction ◽  
Direct Shear Test ◽  
Shear Test ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Direct Shear ◽  
Stiffness Ratio ◽  
Structural Plane

Structural plane is a key factor in controlling the stability of rock mass engineering. To study the influence of structural plane microscopic parameters on direct shear strength, this paper established the direct shear mechanical model of the structural plane by using the discrete element code PFC2D. From the mesoscopic perspective, the research on the direct shear test for structural plane has been conducted. The bonding strength and friction coefficient of the structural plane are investigated, and the effect of mesoscopic parameters on the shear mechanical behavior of the structural plane has been analyzed. The results show that the internal friction angle φ of the structural plane decreases with the increase of particle contact stiffness ratio. However, the change range of cohesion is small. The internal friction angle decreases first and then increases with the increase of parallel bond stiffness ratio. The influence of particle contact modulus EC on cohesion c is relatively small. The internal friction angle obtained by the direct shear test is larger than that obtained by the triaxial compression test. Parallel bond elastic modulus has a stronger impact on friction angle φ than that on cohesion c. Under the same normal stress conditions, the shear strength of the specimens increases with particle size. The shear strength of the specimen gradually decreases with the increase of the particle size ratio.

Stability Analysis of Dam Slope by Double Safety Factors of Dynamic Local Strength Reduction Method

2015 ◽  
Vol 744-746 ◽  
pp. 593-596
Author(s):  
Yuan Meng
Keyword(s):  
Internal Friction ◽  
Reduction Method ◽  
Failure Process ◽  
Friction Angle ◽  
Strength Reduction ◽  
Internal Friction Angle ◽  
Material Strength ◽  
Strength Reduction Method ◽  
Strength Parameters ◽  
Local Strength

When calculating the dam slope failure process, traditional strength reduction method doesn't consider the difference of decay rate between cohesion and internal friction angle and discount the strength parameters for all elements. This paper uses two different reduction factors for material strength parameters, slope cohesion and internal friction angle. Based on the yield approach index criterion, we change the reduction region in time and put forward a double safety factor of dynamic local strength reduction method for engineering analysis of dam slope stability.

scholarly journals Stabilization of Algerian Clayey Soils with Natural Pozzolana and Lime

2017 ◽  
Author(s):  
Khelifa Harichane ◽  
Mohamed Ghrici ◽  
Said Kenai
Keyword(s):  
Shear Strength ◽  
Internal Friction ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Plasticity Index ◽  
Engineering Properties ◽  
High Plasticity ◽  
Expansive Clay ◽  
Clayey Soils ◽  
Natural Pozzolana

Cohesive soils with a high plasticity index present difficulties in construction operations because they usually contain expansive clay minerals. However, the engineering properties of soils can be improved by different techniques. The aim of this paper is to study the effect of using lime, natural pozzolana or a combination of both lime and natural pozzolana on plasticity, compaction and shear strength of two clayey soils classified as CH and CL according to the unified soil classification system (USCS). The obtained results indicated that for CH class clay soil, the plasticity index decreased significantly for samples stabilized with lime. On the other hand, for the soil classified as CL class clay, a high decrease in the plasticity index value was observed for samples stabilized with natural pozzolana compared to those stabilized with lime. Also, both the cohesion and internal friction angle in lime added samples were demonstrated to increase with time. The combination of lime and natural pozzolana exhibits a significant effect on the enhancement of both the cohesion and  internal friction angle at later stages. The lime-natural pozzolana combination appears to produce higher shear strength parameters than lime or natural pozzolana used alone.

scholarly journals Effect of Glutinous Rice Slurry on the Reinforcement of Silt in the Yellow River Basin by Microbially Induced Carbonate Precipitation (MICP): Mechanical Property and Microcosmic Structure

2021 ◽  
Vol 2021 ◽  
pp. 1-23
Author(s):  
Jianwei Yue ◽  
Limin Zhao ◽  
Baoxi Zhang ◽  
Qingmei Kong ◽  
Siyuan Wang ◽  
...  
Keyword(s):  
Internal Friction ◽  
Yellow River ◽  
Friction Angle ◽  
Yellow River Basin ◽  
Reinforced Soil ◽  
Internal Friction Angle ◽  
The Yellow River ◽  
Mass Ratio ◽  
Glutinous Rice ◽  
The Yellow River Basin

The silty clay in the lower reaches of the Yellow River is characterized by loose structure, low strength, and strong capillary effect. Based on the technology of ancient glutinous rice mortar and microbial-induced calcium carbonate precipitation (MICP), experiments on optimal mass ratio of cementitious liquid to bacterial liquid and optimal concentration of cementitious liquid for MICP and improved MICP technology were carried out by measuring the production of CaCO3, and direct shear test and unconfined compressive strength test of plain silt, glutinous mixing silt, and improved silt with MICP and modified MICP were conducted. The microstructure of the reaction products of MICP and improved MICP technology were also evaluated based on scanning electron microscopy (SEM). Research results showed that the mechanical properties of silt with glutinous rice slurry were effectively improved. With the increase in the concentration of glutinous rice slurry, the strength and internal friction angle of soil samples first increased and then decreased, and the cohesion presented a linear increasing trend. When the concentration of cementitious liquid was 0.5 M and the mass ratio of cementitious liquid to bacterial liquid was 2 : 1, the amount of CaCO3 formed was the most, and the conversion rate of Ca2+ was more than 80%. The improved MICP could increase the conversion rate of Ca2+ (93.44%). An improved MICP showed that glutinous rice slurry could improve bacterial activity, increase the urease content in the bacterial solution, and promote the production of CaCO3. Silt cohesion and internal friction angle of the silt were improved by the improved MICP technology, and the strengthening effect of mechanical properties of modified MICP-reinforced soil is better than that of the MICP-reinforced soil; conventional MICP technology could also improve the soil cohesion, but the improvement in the internal friction angle was not obvious. The SEM results indicated that compared with the reaction product of MICP technology, the structure of the product of improved MICP technology is more compact, resulting in a marked reinforcement of MICP performance with glutinous rice slurry. This study provides new insights into enhancing the mechanical behaviour of MICP-treated silt in the Yellow River Basin with glutinous rice slurry.

scholarly journals Field Test Research on Red Clay Slope under Atmospheric Action

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Kaisheng Chen
Keyword(s):  
Internal Friction ◽  
Water Content ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Friction Angle ◽  
Internal Friction Angle ◽  
Red Clay ◽  
Failure Characteristics ◽  
Clay Slopes

By embedding water content sensors and pore water pressure sensors inside the red clay slope on-site in Guiyang, Guizhou, shear tests were performed on soil samples at different depths of the slope under different weather. The changes of water content, pore water pressure, and shear strength index of the slope inside the slope under the influence of the atmosphere were tracked and tested, and the failure characteristics and evolution of the red clay slope were analyzed. It is believed that the depth of influence of the atmosphere on red clay slopes is about 0.7 m, rainfall is the most direct climatic factor leading to the instability of red clay slopes, and the evaporation effect is an important prerequisite for the catastrophe of red clay slopes. The cohesion and internal friction angle of the slope soil have a good binary quadratic function relationship with the water content and density. The water content and density can be used to calculate the cohesion and internal friction angle. Failure characteristics of red clay slopes: the overall instability failure is less, mainly surface failure represented by gullies and weathering and spalling, and then gradually evolved into shallow instability failure represented by collapse and slump. The damage evolution law is as follows: splash corrosion and surface corrosion stage⟶ fracture development stage⟶ gully formation stage⟶ gully development through stage⟶ local collapse stage⟶ slope foot collapse stage.

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