Civil and Environmental Engineering Commons^™

Effects Of Cyclic Loading Directions On Liquefaction Characteristics Of Saturated Coral Sand, Kang Liu, Guo-Xing Chen, Qi Wu, Wei-Jia Ma, You Qin

Rock and Soil Mechanics

The large scale construction of both military and civil infrastructures located in Nansha reefs and offshore marine areas, South China Sea, has raised the seismic safety a challenging issue for the projects in the region. The influences of fines content (FC) on the liquefaction characteristics of saturated terrestrial quartz sands have been extensively studied, but the corresponding research on saturated coral sands in reclaimed coral islands is less involved. Using the GDS hollow cylinder torsion shear apparatus, a series of isotropically consolidated undrained cyclic tests have been performed on saturated coral sand sampled from the Nansha Islands, South China Sea. …

Study On Bearing Capacity Of Permeable Pipe Pile By Field Optical Fiber Monitoring, Jing Wang, Tao Xiao, Hong-Hu Zhu, Guo-Xiong Mei, Zheng-Yuan Liu, Guang-Qing Wei

Rock and Soil Mechanics

Permeable pipe piles are set in the soft soil foundation to accelerate the dissipation rate of excess pore water pressure induced by pile driving and then to accelerate the consolidation of soil around the pile. At present, there are many studies, including model tests and numerical simulation, on the bearing capacity and permeability performance of permeable pipe piles. However, few field tests have been conducted to deeply study the time effect of bearing capacity and load transfer law of permeable pipe piles. Based on the fiber Bragg grating (FBG) technology, the static load tests were carried out to study the …

Analysis Of Laterally-Loaded Piles Embedded In Multi-Layered Soils Using Efficient Finite-Element Method, Hai-Peng Zhao, Xue-You Li, Jian-Hong Wan, Xiang-Zhi Zheng, Si-Wei Liu

Rock and Soil Mechanics

Mechanical analysis of laterally-loaded piles embedded in multi-layered soils is a critical step in design. Traditional finite-element method may have deficiency in accuracy and efficiency when applied to analyze this problem. An efficient finite-element method is proposed in this paper. A “pile element” that adopts the distributed “soil springs” along the element length to reflect the nonlinear behaviors of the pile-soil interactions is developed in this method. The dominant feature of the pile element is the direct integration of soil properties into the element formulation, namely, a pile element comprises both the pile and soil properties. The pile element formulation …

Response Analysis Of Residual Soil Slope Considering Crack Development Under Drying−Wetting Cycles, Yue Liu, Dong-Xia Chen, Hui Wang, Jia-Jing Yu

Rock and Soil Mechanics

In order to study the response of granite residual soil slope with cracks under different number of drying-wetting cycles (D-W cycles), model test was carried out and the crack width expansion index was quantified by investigating the crack images. Based on the direct shear test, the calculation formulas of soil strength degradation and crack depth were developed. Then, the model test and the numerical simulation results were compared to analyze the response of the residual soil slope considering crack extension. The results showed that the fractures width expansion in residual soil under D-W cycles followed the Logistic model, and there …

Statistical Damage Constitutive Model Of High Temperature Rock Based On Weibull Distribution And Its Verification, Hao-Peng Jiang, An-Nan Jiang, Xiu-Rong Yang

Rock and Soil Mechanics

The decrease of rock stability is caused by the possible deterioration of rock mechanical properties under high temperature environment. Therefore, the study of the constitutive behavior of rocks under high temperature is of great significance. Based on the recent researches of statistical rock damage constitutive model, the statistical damage constitutive model of rock after high temperature is established by adopting M-C criterion with the thermal damage variable and Weibull distribution function and the parameter expression is determined. The model is compared with the theoretical curve to verify its rationality. Finally, the model is verified by the uniaxial compression test results …

Experimental Investigation On Surrounding Rock Stress And Deformation Rule Of Tbm Tunneling In Deep Mixed Strata, Yuan-Hai Li, De-Zhu Liu, Shuo Yang, Jun Kong

Rock and Soil Mechanics

To investigate the relation among the stress, deformation, rupture, and stratigraphic effects of surrounding rocks of the supported and unsupported TBM tunnelling in deep mixed strata, the experimental investigation was conducted by a similarity model test system in biaxial plane strain. The stress and strain measurement devices and the self-developed refinement digital photogrammetric measurement system PhotoInfor were applied in this study. The results show that the stress distribution and failure mode are quite different between the upper-soft and lower-hard strata, indicating an obvious non-uniformity stratigraphic effect. The stress in hard rocks is larger than that in soft rocks. As the …

Gap Study For The Impact Of Braced Deep Excavation On The Behavior Of Excavation Bed, Abdelrahman E. Aboelela, Ahmed M. Ebid, Ayman L. Fayed

Future Engineering Journal

Two geotechnical topics were investigated in this research; shored deep excavation and modulus of subgrade reaction. Both topics were extensively studied by many earlier researchers. The aim of this study is to answer the following question, "Is deep excavation effects on excavation bed behavior of sufficiently investigated? Or there still un-studied gaps should be fulfilled?”. Litterateurs were collected, reviewed and classified for both topics especially in the interaction zone between the two topics, and it is concluded that deep excavation effect on the modulus of subgrade reaction values and distribution at excavation bed level is not sufficiently addressed especially the …

Epoxy Glass Fiber Reinforced Plastic Dowel Splice For Prestressed Precast Concrete Pile, Saman Farhangdoust

FIU Electronic Theses and Dissertations

Due to limitations in operation, shipping difficulties, and unforeseen soil conditions, it often happens that splicing of precast-prestressed concrete pile (PPCP) segments has to be performed at the construction site to achieve longer lengths. In order to splice PPCPs, Glass fiber reinforced polymer (GFRP), Carbon Fiber Reinforced Polymer (CFRP), and Stainless Steel (SS) dowels can be used as corrosion-resistant bars. In addition to their durability and superb mechanical performance, GFRP bars show cost advantage when compared to other corrosion-resistant materials. The objective of this study is to investigate the flexural behavior and effectiveness of the GFRP dowel and compare its …

Investigation Of Sand-Biochar Mixtures As A Potential Roadway Fill Material, Katia J. Lele Lagmago

LSU Master's Theses

Biochar is a sustainable and lightweight carbon-rich material with a high surface area and porosity. Previous studies reported that biochar can reduce soil erosion and cracking, retain contaminants, and enhance soil aggregation. Given these favorable properties, soil-biochar mixtures have the possibility to serve as a multifunctional lightweight fill material for roadway embankment applications. The purpose of this research is to develop sand-biochar mixtures as a sustainable and multifunctional lightweight fill material for roadway embankment applications.

This research investigated the consolidation and hydraulic properties of sand-biochar mixtures by (1) performing 1D consolidation tests, (2) performing permeability tests, and (3) assessing the …

Effects Of Loading Rate On Sbpt Responses Of Zhanjiang Structured Clay, Rong-Jun Shu, Ling-Wei Kong, Wen-Zhuo Shi, Bing-Heng Liu, Cheng-Sheng Li

Rock and Soil Mechanics

No abstract provided.

Effect Of High Temperature On Micro-Structure And Permeability Of Granite, Shen-Yuan Deng, Qing-Hui Jiang, Kai-Wei Shang, Xiang-Yang Jing, Feng Xiong

Rock and Soil Mechanics

No abstract provided.

Experimental Study On Cyclic Shear Softening Characteristics Of Gravel−Geogrid Interface, Fei-Yu Liu, Huai Jiang, Jun Wang

Rock and Soil Mechanics

No abstract provided.

System Failure Probability Analysis Of Cohesive Slope Considering The Spatial Variability Of Undrained Shear Strength, Hui Liu, Jun-Jie Zheng, Rong-Jun Zhang

Rock and Soil Mechanics

A system failure probability analysis method of cohesive slope considering the spatial variability of undrained shear strength is proposed. In this method, the local averaging parameter of the random field of undrained shear strength on slip surface is introduced as an equivalent parameter. The statistical characters of the equivalent parameter and the correlation coefficient between different equivalent parameters are formulated. Then, the reliability index of a single failure mode and the correlation coefficient between different failure modes are calculated based on the equivalent parameters. By considering both the reliability index and correlation coefficient between different failure modes, the representative slip …

Water Retention Curve Model Based On Micro-Pore Filling And Capillary Condensation Theories, Zhang-Rong Liu, Wei-Min Ye, Yu-Jun Cui, He-Hua Zhu, Qiong Wang, Yong-Gui Chen

Rock and Soil Mechanics

Water retention curve (WRC) is an important tool to study the hydraulic and mechanical properties of unsaturated soils, such as permeability, strength and deformation properties. Most of the existing WRC models fail to reflect the water retention mechanisms of unsaturated soils or they are complex in form, and these models are hard to give good performance on modelling the bimodal and multimodal WRCs. In this study, based on analyzing the water retention mechanisms of unsaturated soils, the WRC was divided into two domains that are governed by adsorption and capillary mechanisms, respectively. An adsorption water retention curve model (WRCM) was …

Experimental Study On Brazilian Splitting Of Phyllite Under The Coupling Effects Of Water, Pore And Bedding, Chuang Zhang, Song Ren, Ping Zhang, Neng-Zeng Long

Rock and Soil Mechanics

Phylite is widely distributed in southwest of China. Factors such as groundwater, bedding, micro-pores and micro-cracks will weaken its mechanical properties to some extent, thus posing severe challenges to the stability of the related projects. Therefore, in this paper, based on Brazilian splitting test, the evolutions of the tensile strength, energy and failure forms of phyllite under the coupling effects of water, bedding and pore are studied. The results show that the tensile strength decreases gradually with the increase of moisture content, pore diameter and bedding angle. However, the tensile strength has different sensitivities to the changes of them, which …

A New Solution To The Ultimate Bearing Capacity Of Reinforced Ground Near Slope Based On The Unified Strength Theory, Qing Yan, Jun-Hai Zhao, Chang-Guang Zhang

Rock and Soil Mechanics

In view of two modes of general shear failure and composite failure of reinforced ground, a new solution to the ultimate bearing capacity of strip footings resting on reinforced ground near slope was derived based on the unified strength theory and the application procedures were given. Effects of the intermediate principal stress, the vertical spacing between reinforced material layers, the number of reinforced material layers, and the tensile strength of reinforced materials were comprehensively taken into consideration in the new solution. Compared with other methods, the effectiveness and parameter influence characteristics of the proposed method were discussed. The results showed …

Fracturing Mechanism Of Rock-Like Specimens With Different Joint Densities Based On Dic Technology, Fei-Fei Qi, Ke Zhang, Jian-Bin Xie

Rock and Soil Mechanics

In order to study the influence of joint density on the strength characteristics and failure modes of rock mass, the rock-like specimens with different joint densities were prepared by using 3D sand printing, with the quartz sand and furan resin being employed as the printing materials. The uniaxial compression test was performed on the 3D sand printed specimens, and the digital image correlation (DIC) method was used as a non-contact technique to monitor the full-field deformation. The crack initiation, propagation and coalescence behaviors were quantitatively analyzed from the micromechanics point of view. The results show that the shape of stress-strain …

Rainfall Infiltration Analysis And Infiltration Model Of Slope Based On In-Situ Tests, Zhi-Hui Guo, Wen-Bin Jian, Qing-Ling Liu, Wen Nie

Rock and Soil Mechanics

Typhoon rainstorms occur frequently in the southeastern coastal areas of China. The infiltration of rainwater under typhoon rainstorm conditions is an important cause of landslides in hilly mountains. Therefore, it is of great significance to study the migration law of rainwater infiltration wetting front under different geological environmental conditions. The temporal and spatial changes of rainfall infiltration were analyzed based on the monitoring data collected by the in-situ test of a landslide. A comprehensive rainfall infiltration model was established, which takes into account the nonuniform distribution of the initial water content of the soil and the slope environment. Then this …

Density State And Shear Behavior Of Granular Soils With Influence Of Particle Size Distribution, Yibing Deng

Doctoral Dissertations

Heterogeneous granular soils are ubiquitous in nature and man-made deposits. Heterogeneity of soil is characterized by its particle size distribution (or fines content for gap-graded soils). The particle size distribution of soil is the main factor that affects its mechanical properties. However, in soil mechanics, the influence of particle size distribution on mechanical properties is only considered in an empirical manner. There are few analytical methods that can explicitly account for the effect of particle size distribution. In this study, there are two purposes: 1) to develop a particle packing theory for modeling the effect of particle size distribution on …

Undrained Cyclic Loading Of Low Plasticity Silty Soils In The Pacific Northwest Using Laboratory And Field Cyclic Shear Testing, Angelica Melissa Preciado Reyes

Dissertations and Theses

The cyclic behavior of a fine-grained low plasticity silty soil (plasticity index of approximately 15) at a site in Portland, Oregon, is characterized using a field and laboratory cyclic shear test program. The field cyclic tests were performed using the NHERI@UTexas large mobile shakers T-Rex and Rattler. The laboratory tests were performed using resonant column torsional shear and cyclic direct simple shear devices. This testing program's results were used to evaluate the soil's potential to develop excess pore water pressure with cyclic shear strains ranging from 0.00001% to 3%. The laboratory cyclic test results are compared against field cyclic test …

Geological Origin As An Input Variable In Reliability-Based Designs: For An Accurate Exploration In Geotechnical Engineering, Juan Camilo Viviescas, Juan Pablo Osorio

Conference papers

Soil is one of the most difficult materials to characterize realistically, which partly explains the uncertainty between the designs and the geostructures real behavior. Different recommendations have arisen with respect to carrying out field investigations in order to reduce the uncertainties inherent to the soil. However, the field exploration and the implementation of sophisticated geotechnical models have proven to be insufficient to mitigate the geotechnical uncertainty. Therefore, Reliability-Based Designs (RBD) emerge as a decision-making tool through the definition of the probability of failure in conjunction with the typical Factors of Safety. RBD requires a previous understanding of the most appropriate …

Development Of A New Electro-Osmotic Consolidation Apparatus, Yenni Mariana Ramírez-Mazo, Juan Pablo Osorio, Sergio Agudelo

Conference papers

Electro-osmotic consolidation is a ground improvement technique in which a DC voltage is applied to the soil via electrodes, in order to drain the water contained in the pores increasing the effective stress, and thus improving the geotechnical properties of the soil. The technique increases the shear strength, reduces the compressibility, and changes the chemical composition of the saturated soft clayey and silty soils to which it can be applied. Electro-osmotic consolidation has been successfully applied in different projects worldwide. This paper presents the development of a new electro-osmotic consolidation apparatus built at Universidad de Antioquia. Tests were carried on …

An Exploration Of Lean And Bim Synergies With A Focus On Smes In Construction, Barry Mcauley, Marina Andreou, Alan V. Hore, Avril Behan

Conference papers

Small and Medium Enterprises (SME) account for 99.7% of the Irish Construction Industry and contribute to 68% of all employment in the sector. These organisations now find themselves facing the challenge of returning to productive business post the Covid 19 shutdown. More than ever, SMEs must modernise and adapt their business models to embrace new ways of working, such as Lean Construction and Building Information Modelling (BIM), in the absence of clear business incentives. It has proved difficult to persuade SMEs to change their ways of working due to limited finances, internal resources and above all, the cultural shift required …

Simulation Of Debris Flow Impacting Bridge Pier Tests Based On Smooth Particle Hydromechanics Method, Heng Liang, Ji-Lin Li, Fa-Ming Liu, Lun Zhang, Gang Fu, Ming-Qing Li, Si-Ming He

Rock and Soil Mechanics

In this paper, a three-dimensional numerical simulation model is established based on smooth particle hydrodynamics (SPH) method. In this model, the dynamic behavior of debris flow is described by using the Bingham fluid model, and the bridge pier is regarded as the terrain condition. The repulsive force at the boundary is introduced to improve the boundary condition. Based on flume experiments, the accumulation processes of debris flow impacting the bridge pier with various viscosities and characteristics of the impact force-time curves are analyzed. The physical models are established, and the simulation of three-dimensional dynamic evolution processes of debris flow impacting …

Rock Plastic-Damage Constitutive Model Based On Energy Dissipation, Qiu-Feng Ma, Zhi-He Liu, Yue-Ping Qin, Jing Tian, Shu-Li Wang

Rock and Soil Mechanics

In this paper, the dissipative energy in the damage process was employed to solve the damage variable while the damage constitutive model was established. In this model, the Mohr-Coulomb criterion and the energy dissipation theory were introduced. Considering the hardening and softening characteristics of rock during loading, the non-associated plastic flow rule was applied to describe the plastic deformation of rock, and the damage variable was calculated by quoting the dissipation energy and damage energy dissipation rate in the damage process. Based on the conventional triaxial loading-unloading experiments, the energy consumption and damage evolution law of rock was analyzed. The …

Experimental Study Of Filtration & Fine Particles Migration Of Calcareous Sand In Coral Reef Island, Yuan-Jiang Ju, Ming-Jian Hu, Kun-Kun Qin, Bo Song, Zi-Chen Sun

Rock and Soil Mechanics

Due to its unique biogenesis, forming environment and deposition process, calcareous sand is featured with irregularity, brittleness, weak structure and low cohesion, and is considered substantially different from the common terrestrial sand deposits. Fine particles bonded with weak cohesion may be resolved by osmotic action and then migrate and reaccumulate, thus causing changes in porosity and permeability. This study has carried out filtration experiment and laser particle size analysis of exudate sediment under different initial conditions to analyze the principles of evolution, involving permeability coefficient and the characteristics of fine particle transporting during the filtration process in calcareous sand. The …

Joint Arrival-Time Picking Method Of Microseismic P-Wave And S-Wave Based On Time-Frequency Analysis, Bao-Xin Jia, Feng Li, Lin-Li Zhou, Shuai Wang, Jia-Shun Liu

Rock and Soil Mechanics

Accurate acquisition of arrival time of microseismic signals is an important prerequisite for focal location, and the accurate acquisition of arrival time of P-wave and S-wave of microseismic signals has important theoretical significance. Based on the principles of time-frequency analysis and the arrival-time picking, the time-frequency analysis-downhill comparison method is proposed. According to the time-frequency analysis principle of this method, the position and rule of background noise, the frequency, amplitude and energy of microseismic signals before and after the initial arrival of P-wave and S-wave and smooth waveforms that facilitate the comparison of iterative averages can be obtained through spectrogram, …

Analytical Solution To Consolidation Of Unsaturated Soil By Vertical Drains With Continuous Permeable Boundary, Ai-Fang Qin, Liang-Hua Jiang, Wei-Fang Xu, Guo-Xiong Mei

Rock and Soil Mechanics

In this paper, based on the axisymmetric consolidation theory of unsaturated soil and equal-strain assumption, an analytical solution using the homogenization of boundary conditions and eigenfunction method is proposed to three-dimensional consolidation of unsaturated soil enhanced by vertical drains under instantaneous loading, in which the continuous permeable boundary conditions are properly introduced. Then, the proposed solution is verified by the special cases of double drainage boundary conditions. Finally, the solution is analyzed using examples and the results show that the proposed solution can be used to simulate the arbitrary distribution of permeability of the top and bottom boundary by setting …

Experimental Study Of Unsaturated-Saturated Permeability Characteristics Of Slip Zone Soil In Deposits, Yue Li, Wei-Ya Xu, Kui Yi, Wei-Chau Xie, Qiang Zhang, Qing-Xiang Meng

Rock and Soil Mechanics

There are many landslide deposits in the reservoir and bank areas of hydropower projects in southwest China. These deposits are easy to deform and fail along the existing sliding zone under hydrodynamic conditions, such as rainfall and reservoir water fluctuation. The slip soil in Dahua landslide deposits which are located at the Dahuaqiao Hydropower Plant in the Lancang river basin of southwest China, was studied as an example. The experimental study was carried out to explore the soil-water characteristic curve (SWCC) of slip soil. The permeability characteristics and the evolution in the unsaturated seepage process were analyzed, and the saturated …

Influence Of Rock Mass Spatial Variability On Probability Of Tunnel Roof Wedge Failure, Wen-Gang Zhang, Qi Wang, Han-Long Liu, Fu-Yong Chen

Rock and Soil Mechanics

In tunnel design and construction, the stability evaluation of tunnel roof wedge usually adopts traditional deterministic analysis methods, which cannot appropriately reflect the spatial variability of rock mass. Based on limit equilibrium method, an efficient approach for evaluating the safety factor integral expression of tunnel roof wedge is presented in this study. This approach considers the influence of spatial variability of rock mass joint friction angle and is validated by universal distinct element code (UDEC). Based on random field method and Monte Carlo simulation (MCS), a generated random field is substituted into the established safety factor integral expression to calculate …