Geotechnical Engineering Commons^™

Experimental Study On Shear Strength Of Unsaturated Soil Over A Wide Suction Range And Its Prediction, Geng Niu, Xiao-Feng Zhu, Jun-Xing Li, Meng-Yuan Lü, Li-Qi An, Zi-Han Chen

Rock and Soil Mechanics

In this paper, the experimental studies on the water retention and strength properties of unsaturated weakly expansive soil in a wide suction range were carried out, and a strength model of unsaturated soil over a wide suction range was proposed. The results show that in the wide suction range, the stress‒strain curve increases with the increase of suction. The strain hardening occurs in the low suction range, while the strain softening appears in the high suction range. In the low suction range, the sample presents shear contraction, while in the high suction range, the sample begins to show a shear …

Shear Strength Characteristics Of Unsaturated Rubber Silt Mixtures, En-Quan Zhou, Yuan Yao, Lei Cui, Long Wang

Rock and Soil Mechanics

To study the shear strength characteristics of unsaturated rubber silt mixtures, a series of direct shear tests was conducted on the rubber silt mixtures with different rubber particle contents and water contents. Based on the particle contact state theory, the meso contact mode of rubber silt mixtures was constructed, and the calculation method of rubber silt mixtures skeleton void ratio based on different rubber content was obtained. The test results show that the shear strength of rubber silt mixtures decreases with the increase of skeleton void ratio at a low water content, while the strength of rubber silt mixtures increases …

An Improved Shear Strength Model Of Unsaturated Soils Over A Wide Suction Range, Yu-Xin Zhao, Xu Li, Sen Lin, Xiao-Meng Wang

Rock and Soil Mechanics

Different types of unsaturated soils are widespread in nature. Due to the differences in grain size and mineral composition, the shear strength characteristics of the unsaturated soils are significantly different over a wide suction range. In order to establish a unified model for predicting the shear strength of different soil types over a wide suction range, a systematic investigation was carried out to examine the effect of soil type on the shear strength of unsaturated soils. An improved shear strength model is proposed based on the advantages of two traditional equations. The proposed model is verified by comparing the published …

Experimental Research On The Shear Characteristics Of The Composite Liner Consisting Of Wrinkled Geomembrane And Needle Punched Geosynthetic Clay Liner, Hai Lin, Yi-Fan Zeng, Chuang-Bing Zhou, Ping-Xiao Dong, Jian-Yong Shi

Rock and Soil Mechanics

Wrinkles in geomembrane are common among anti-seepage engineering. However, the wrinkling effect has been neglected in most of the current studies on the interface shear properties of geomembrane. The composite liner consisting of a textured geomembrane (GM) and a needle punched geosynthetic clay liner (GCL) was taken as the research object, and the hydration deformation tests confirmed that the two-step hydration method was effective in accelerating the hydration of the wrinkled GM+GCL composite liner. The shear properties of the wrinkled GM+GCL composite liner was studied by a large-scale temperature-controlled submerged direct shear apparatus. The shear characteristic of the wrinkled GM+GCL …

Correlations Between Dynamic Probe Blow Count And Undrained Shear Strength For Peat At A Well-Characterised Raised Bog In Ireland, David Mchugh, Ciaran Reilly, Juan Pablo Osorio

Articles

Peat deposits are generally heterogeneous, with large variations over small areas. Peat has an extremely high water content, high compressibility and low shear strength. This presents a major issue in studying the geomechanical behavior of peat. For this study, field and laboratory tests were conducted to establish the undrained shear strength (s_u) of peat at a cutover industrial peatland in Ireland which had been extensively characterized in the past. The new field work included TRL-type Dynamic Cone Penetrometer, Mackintosh probe and field vane shear tests. A correlation was developed between the Mackintosh probe “M-value” blow count and the …

Mechanical Properties Of Saline Soil Solidified With Lime, Fly Ash And Modified Polyvinyl Alcohol Under Freeze-Thaw Cycles, Min Li, He-Miao Yu, Hong-Pu Du, Bao-Yu Cao, Shou-Xi Chai

Rock and Soil Mechanics

The repeated freeze-thaw cycles with seasonal alternations have an obvious effect on soil structure. To reduce the temperature sensitivity of saline soil and then use it in engineering, a combined treatment method is proposed, where lime, fly ash and modified polyvinyl alcohol (MPA) are used as solidified materials. Unconfined compressive strength (UCS) tests and microstructure characterization are firstly used to evaluate the solidified effect and obtain the parameters range of solidified materials. Then, the shear strength tests for determining cohesion and internal friction angle are conducted. Experiments are conducted by considering separate and combined treatments of materials mentioned above. The …

Improvement Of Slope Soil Consolidation Capacity Of Plant Root System Based On Regulation Of Root Architecture, Zhen-Yu Li, Miao Ouyang, Hong-Bin Xiao, Ju-Shan Wang, Tao Li, Si-Si Liu

Rock and Soil Mechanics

The effect of plant slope protection is strongly associated with the root architecture in soil. In this paper, the water?fertilizer combination method was used to regulate the plant root configuration, and the influence of the regulated plant root architecture on the slope soil strength was studied. In terms of the practice of highway slope engineering, a field fill slope for test was made. Vetiver was selected as slope protection species, and 9 groups of water?fertilizer combinations were designed to regulate the root architecture of plant in slope soil. After 10-months growth, the roots of plants on the slope were counted …

Examination Of The Correlation Between Shear Strength, California Bearing Ratio, And Index Properties Of Fine-Grained Soil, Billy W. Rushema

Master of Science in Civil Engineering Theses

Abstract

California Bering Ratio (CBR) is used to evaluate the strength of the pavement materials by comparing bearing capacity of the material with that of a high-quality crushed stone. This test adopted by transportation agencies and widely used in the design and analysis of pavement. Several agencies developed design thickness chart based on the CBR values of the subgrade. However, CBR test is time consuming and expensive to perform compared to shear strength test and therefore several studies have been conducted to establish correlation between shear strength and CBR. The published correlation models between CBR and shear strength of soil …

Shear Strength Calculation Model Of Rock Joints Based On Three-Dimensional Morphology Of Joint Surface, Lei-Lei Jin, Yu-Feng Wei, Xin Huang, Jie Wei

Rock and Soil Mechanics

The JRC-JCS model, which is widely used in the field of geotechnical engineering, has the following defects: 1) the two-dimensional joint roughness coefficient (JRC) can’t comprehensively represent the anisotropy of joint surface morphology; 2) the joint compressive strength (JCS) of joint wall can’t entirely reflect the influence of material properties on joint shear mechanical behavior. In this paper, artificial joint samples with natural joint morphology were poured based on three-dimensional laser scanning and three-dimensional printing technology, and shear tests under constant normal stress were carried out. The shear strength model with three-dimensional morphology parameters and tensile strength parameters was established …

Effect Of Particle Size Distribution And Packing Characteristics On Railroad Ballast Shear Strength: A Numerical Study Using The Discrete Element Method, S. M. Naziur Mahmud

Boise State University Theses and Dissertations

Railroad infrastructure plays a significant role in sustaining the economy of a country, and facilitates fast, safe and reliable transportation of passengers as well as commodities. Significant capital investments are required for the construction and maintenance of a railroad network that is structurally and functionally adequate. The ballast layer is one of the main structural components of a conventional rail track system, and comprises coarse-grained unbound particles, often as large as in size. The ballast as a load-bearing layer resists train-induced stresses through particle-particle interaction. Accordingly, particle-size distribution and packing characteristics are important factors that govern the mechanical behavior of …

Propiedades Geotécnicas De La Turba Intervenida Antrópicamente, Juan Pablo Osorio

Conference papers

La intervención antrópica en turberas genera cambios significativos en las propiedades geotécnicas de un material orgánico, altamente compresible y con baja resistencia al esfuerzo cortante. Existen diferentes formas de intervención, dependiendo de las tradiciones de cada lugar. Sin embargo, los procesos de intervención más comunes son la precarga por medio de terraplenes y el drenaje, las cuales generan una reducción en el contenido de humedad, la compresibilidad y la permeabilidad, así como un incremento en la resistencia al esfuerzo cortante. En el presente artículo, se discute el efecto de la intervención antrópica en las propiedades geotécnicas de las turbas, a …

Deformation And Shear Behaviors Of Weathered Compacted Shale, Xu Zhang

Theses and Dissertations--Civil Engineering

As an abundant sedimentary rock, shale is widely used as construction material around the world. However, shale is a fissile and laminated material and is therefore subject to deterioration due to environmental and chemical forces (i.e., weathering), which is possible to cause high maintenance cost on associated structures and failures of earth slopes and embankments. However, currently, there is lack of efficient method to monitor the weathering process of shale. This thesis uses several shale samples collected from the commonwealth of Kentucky to study the deformation and shear behaviors of weathered compacted shale. A new electrical approach was developed to …

Strength And Deformation Of “Tunable” Clay-Polymer Composites, Matthew David Bishop

Masters Theses

There are many different types of clay that exist throughout the world, and many are characterized by undesirable engineering properties. Soil improvement techniques are often implemented on these soils such as solidification, reinforcement, etc. However, these solutions are a “static” approach, as the soil’s properties cannot be modified over time. The development of the specific clay-polymer composites used in this study was motivated by the idea of creating a geomaterial that could be modified over time by adjusting its fabric, namely in the form of controlling interparticle and interlayer spacings. Therefore, the composites that are used in this study are …

Electrokinetic Dewatering Of Oil Sands Tailings, Yu Guo

Electronic Thesis and Dissertation Repository

Oil sands tailings are the final product of oil sands processing and in the form of slurry with very low solid content. After sedimentation, due to a low hydraulic conductivity of the tailings, both dewatering and consolidating the tailings are difficult. Since electrokinetic (EK) is an effective method to consolidate low permeability soils, the objective of this study is to assess the effectiveness and efficiency of EK dewatering of MFT, a man-made geomaterial. Two series of tests were conducted in this study. In the first series, four EK cell tests were performed on oil sands tailings to measure the electroosmotic …

Geotechnique, Physico-Chemical Behaviour And A New Erosion Model For Mine Tailings Under Environmental Loading, Rozalina S. Dimitrova

Electronic Thesis and Dissertation Repository

Comprehensive geotechnical characterisation of mine tailings is required for the design, construction and safe operation of mine waste management facilities against the large number of potential failure risks. It is important that the characterization is carried out under the stress range and drainage conditions relevant to those encountered in the field.

The present research utilized mine tailings samples from a copper/nickel base-metal mine. Kaolinite and bentonite clays were added to the mine tailings in order to study the effect of clay percentage and clay mineralogy on the behaviour of saturated tailings/clay systems with varying composition. Slurries with moderate or high …

Investigation Of The Geotechnical Properties Of Municipal Solid Waste As A Function Of Placement Conditions, Wilson W. Wong

Master's Theses

An investigation of the variability of engineering properties of municipal solid waste as a function of placement conditions was conducted. Limited data have been reported for the engineering properties of municipal solid waste (MSW) as a function of placement conditions. Wastes have high variability of engineering properties due to heterogeneity in composition and component size; influence from time based effects; and presence of compressible solids. Control of moisture content of MSW at the time of waste placement provides opportunity for increased capacity at a given landfill site due to higher compacted unit weight as well as for control of other …