Civil and Environmental Engineering Commons^™

Dynamic Response Of A Track Coupled With A Transversely Isotropic Ground Due To Train Axle Loads, Yi-Cheng Li, Shi-Jin Feng

Rock and Soil Mechanics

To study the environmental vibrations induced by train loads, an analytical model for a track coupled with a layered transversely isotropic (TI) ground is developed. The model can consider the alternate distribution of TI elastic and poroelastic layers in the ground to describe soils and rocks under different moisture conditions compared with existing models comprising only one type of medium. Based on the analytical model, the governing equations of TI media are solved firstly using Fourier transform and a potential function method. Then the exact stiffness matrix method is adapted to derive solutions to the layered ground with different media. …

Lateral Spreading And Stability Of Embankments Supported On Fractured Unreinforced High-Modulus Columns, Aaron P. Gallant, Danilo Botero Lopez

Non-Thesis Student Work

Construction of column-supported embankments (CSEs) with unreinforced high-modulus elements is now common practice to accelerate fill placement. These brittle columns are susceptible to column fracturing and CSE designs often limit the degree of lateral spreading such that tensile rupture will not occur, which stems from salient concerns that fracturing may trigger uncontrolled lateral spreading and/or the cessation of intended vertical load transfer. However, tensile rupture is unlikely to coincide with full mobilization of available passive resistance at the toe. Thus, it is disputed in industry whether some degree of column fracturing is tolerable. The objective of this study is to …

Effect Of Moisture Content On Characteristic Stress And Acoustic Emission Characteristics Of Red Sandstone, Kui Zhao, Shan-Hu Ran, Peng Zeng, Dao-Xue Yang, Tian-Ye Teng

Rock and Soil Mechanics

In order to investigate the response law of moisture content to the characteristic stress and acoustic emission characteristics of red sandstone, the uniaxial compression tests of red sandstone under different moisture content conditions were conducted using RMT-150C rock mechanical pressure testing machine and PCI-Ⅱ AE win acoustic emission system. The physical and mechanical parameters and characteristic stress evolution mechanism of red sandstone under water erosion are analyzed, and the evolution law of acoustic emission (wide and narrow-band) time series mode under different moisture content conditions is also investigated. At the same time, the damage evolution model of red sandstone is …

Influence Of Gas Migration Patterns On Reinforcement Of Dredged Slurry By Air-Booster Vacuum Preloading Method, Hua-Yang Lei, Peng Wang, Xu Liu, Lei Wang

Rock and Soil Mechanics

In this study, laboratory tests of the air-booster vacuum preloading method with different air-boosting depths were performed on the Tianjin dredged slurry of high water content. The law of gas migration in soil was used to analyze the reinforcement mechanism and the reinforcement factors. Test results show that the drainage, settlement, dissipation of excess pore water pressure as well as the vane shear strength were significantly improved when air boosting is operated on the lower part of drainage board. In the initial stage of consolidation of the fluid-plastic soil, the injected gas is easy to form bubbles and to move …

Experimental Study On The One-Dimensional Nonlinear Consolidation And Seepage Of Saturated Clay Considering Stress History Under Ramp Loading, Le Zhang, Fa-Ning Dang, Jun Gao, Jiu-Long Ding

Rock and Soil Mechanics

To study the permeability of saturated clays with different stress histories under ramp loading, the one-dimensional consolidation and seepage tests are carried out using modified GDS triaxial apparatus, and the change of the permeability coefficient of remolded silty clay in Luochuan, Shaanxi Province is studied. The results show that permeability coefficients of normally and over-consolidated saturated clays decrease nonlinearly with the increase of the consolidation stress, and the void ratios of these two soils are consistent with the trend of change of the permeability coefficients with the consolidation stress. The compressibility and permeability of soil in the overconsolidated state are …

Physical Model Experiment On Failure Mechanism And Npr Anchor Cable Control Effect Of Layered Counter-Tilted Slope, Zhi-Gang Tao, Shu-Lin Ren, Yu Hao, Qiang Li, Qiang Fu, Man-Chao He

Rock and Soil Mechanics

Taking the large-scale toppling failure counter-tilted slope in Changshanhao open-pit mine in Inner Mongolia as engineering background, a layered counter-tilted slope geological generalized physical model was constructed based on similar theory. Physical model tests were performed under three different conditions: unreinforced, ordinary Possion’s Ratio(PR) anchor cable reinforcement, and constant resistance and large deformation Negative Possion’s Ratio (NPR) anchor cable reinforcement. Then infrared thermal imaging system, strain monitoring system and digital speckle displacement measurement system were used comprehensively to monitor the temperature field, strain field and displacement field respectively during the entire counter-tilted slope excavation test. Finally the deformation characteristics and …

A Multi-Scale Coupling Finite Element Method Based On The Microscopic Of Soil Particle Motions, Jia Liu, De-Luan Feng

Rock and Soil Mechanics

Soil is a multi-phase and multi-scale geomaterial that exhibits dramatically inhomogeneous and discontinuous physical nature. Conventional finite element method, which is conceptualized at a single macroscale and ignores the control mechanism of soil at the micro and meso scales, cannot reproduce and predict the multi-scale and hierarchical failure of soil. In order to investigate the influence of the physical details and kinematic characteristics of soil at the microscale associated with the global mechanical responses, a multi-scale particle micro-rotation theory is established according to the concept of the soil cell element model. The method is implemented into a multi-scale finite element …

Effect Of Different Notch Prefabrication Methods And Notch Lengths On Rock Three-Point Bending Test, Hao Lu, Xia-Ting Feng, Cheng-Xiang Yang, Xi-Wei Zhang

Rock and Soil Mechanics

To select an appropriate notch prefabrication method and notch length for obtaining relatively accurate and reliable rock mode I fracture toughness (K_IC), as well as to improve understanding of macro fracture process and meso-fracture characteristics in the rock three-point bending test, three methods, i.e., wire cutting, saw blade cutting and water jet cutting were used to prefabricate notch in granite and marble specimens for three-point bending test. The comparison of micro fracture characteristics among three different cutting methods was conducted with the application of scanning electronic microscopic. The test results show that the effect of wire cutting …

Analytical Solutions For 1d Consolidation Of Unsaturated Soils With Mixed Nonhomogeneous Boundary Conditions, Dao-Sheng Ling, Tian-Hao Zhao, Jia-Jun Niu, Song Zhu, Zhen-Dong Shan

Rock and Soil Mechanics

The consolidation of unsaturated soil is of great significance to road engineering, soft foundation soil improvement, etc. Based on the one-dimensional consolidation theory of unsaturated soil proposed by Fredlund and Hasan, the governing equations for pore water pressure and pore air pressure in the soil are established. The initial conditions and a type of time-dependent mixed nonhomogeneous boundary conditions of single-layer unsaturated soil are presented which constitutes the solution of 1D consolidation of unsaturated soil. The homogenization of nonhomogeneous boundary conditions and the eigenfunction expansion method are adopted to derive exact analytical solutions in time domain for the dissipation of …

Evaluation Of The Effect Of Natural Seawater Solidifying Calcareous Sand Based On Micp, Bo-Wen Dong, Shi-Yu Liu, Jin Yu, Yang Xiao, Yan-Yan Cai, Bing-Xiong Tu

Rock and Soil Mechanics

The natural seawater was used to carry out the experiment of microbial culture and microbial-induced calcium carbonate precipitation (MICP) to solidify calcareous sand. First, the effect of seawater on microbes was studied through the growth and reproduction of microbes and the change of urease activity. Then, the effect of seawater on the solidifying effect of MICP was evaluated according to the changes of calcareous sand permeability and unconfined compressive strength (UCS) before and after MICP treatment. Finally, the mechanism of the effect of seawater on the solidifying of calcareous sand by MICP was analyzed by SEM and XRD tests. The …

Scaled Physical Modeling Of The Dynamics Of Granular Flow In Hopper Silos, Hagos Eman

Electronic Thesis and Dissertation Repository

To understand the challenges on grain flow during handling in hoppers and silos require better understanding of the granular physical flow characteristics through experiments done at large scale. However, due to the complexity of the large, controlled tests, scaled models are often used to study the behaviour. Very few of these model scale studies had been done appropriately taking the effects of gravity on silo discharge into account. This subject has also been widely investigated in different areas of geotechnical engineering related to soil erosion, land slides, and dynamic liquefaction. Granular flow rate and the dynamics of the flow are …

Performance Assessment And Design Guidelines For Rc Three-Sided Culverts, Safwat Hassan Ramadan

Electronic Thesis and Dissertation Repository

Reinforced concrete three-sided culverts (TSCs) are typically produced in large spans, up to 16.0 m, and low-rise profiles to handle heavy flows at sites with limited vertical clearance. Full-scale field studies and numerical analyses investigating TSCs do not exist to date. Accordingly, the current design practices specified in the Canadian Highway Bridge Design Code, CHBDC (CSA, 2014) and the American Association of State and Highway Transportation, AASHTO (AASHTO LRFD, 2014) do not distinguish between small-span box and large-span TSCs. A comprehensive study involving field monitoring and numerical analyses of TSCs is presented in this thesis. Three TSCs were instrumented to …

Comparison Of Land Use And Flowslide Incidence In Palu Valley Following The 2018 Mw 7.5 Palu-Donggala Earthquake, Peta C. Fifield

Electronic Theses and Dissertations

The September 28 Mw 7.5 Palu-Donggala earthquake in Indonesia was the deadliest natural disaster in 2018. Five flowslides on the eastern side of Palu Valley, which were attributed to the substantial majority of deaths and economic losses in the region, occurred due to liquefaction of naturally dry alluvial deposits in gently sloping ground (2 to 6%). The requisite conditions for soil liquefaction are the presence of loose granular sediments and full saturation. Instigation of these catastrophic ground failures were linked to artificial saturation by an unlined agricultural irrigation canal. From a civil engineering perspective, the Palu ground failures on the …

Develop A Multi-Functional Green Pervious Concrete (Mgpc) Pavement With Polycyclic Aromatic Hydrocarbons (Pahs) Removal Function., Hong Shang

Electronic Theses and Dissertations

Stormwater runoff induced Polycyclic Aromatic Hydrocarbons (PAHs) contaminant increasingly imperils the groundwater quality and the sustainable development of human society due to the potential carcinogenic risks. Pavement can be considered as the first line of defense for contaminant removal of the stormwater runoff. New construction materials with stormwater runoff quantity and quality control are in urgent demand for updating the existing pavement system. An innovative material called Multi-functional Green Pervious Concrete (MGPC) was developed in the department of Civil and Environmental Engineering at University of Louisville. This material uses organoclay as the amendment to enhance the PAHs removal capacity of …

Experimental Investigation On Dynamic Properties Of Soft Clay Under Coupled Cyclic-Seepage Loads, Hua-Yang Lei, Ying-Gang Xu, Jiang-Yan Miao, Xu Liu

Rock and Soil Mechanics

In this paper, a series of triaxial tests under coupled cyclic-seepage loads were carried out for saturated soft clay in Tianjin. The results show that the development of cumulative plastic strain is characterized by three stages: initial instantaneous growth, decelerated increase and stable / linear development, and seepage can enlarge the dynamic deformation up to 1-2 times of that compared to cyclic load only. Larger seepage force induces greater cumulative plastic deformation. The lower frequency or greater cyclic stress amplitude induces larger strain. The prediction model of cumulative plastic deformation of soft clay is established under the condition of dynamic- …

Prediction Model For Compressive Strength Of Rock-Steel Fiber Reinforced Concrete Composite Layer, Meng Chen, Xiu-Wen Cui, Xin Yan, Hao Wang, Er-Lei Wang

Rock and Soil Mechanics

To study the uniaxial compressive strength calculation method of rock-steel fiber reinforced concrete (R-SFRC) composite layer, uniaxial compression test was carried out on rock, steel fiber reinforced concrete and R-SFRC composite layer specimens. The influence of concrete strength grades (C30, C40 and C50) and fiber contents (0, 40, 60 and 80 kg/m3) on the uniaxial compressive strength of steel fiber reinforced concrete and composite layers was analyzed. RFPA2D was utilized to simulate the damage process and stress-strain curve of the composite layer under uniaxial compression. The compressive strength prediction model of R-SFRC composite layer was established based on Mohr-Coulomb yield …

Large Strain Consolidation Of Sand-Drained Ground Considering The Well Resistance And The Variation Of Radial Permeability Coefficient, Wen-Hao Jiang, Liang-Tong Zhan

Rock and Soil Mechanics

Based on Barron’s equal strain consolidation theory of sand-drained ground and Gibson’s one-dimensional large strain consolidation theory, and considering the well resistance of drains, the variation of radial permeability coefficient and the vertical flow, a more general governing equation of large strain consolidation of sand-drained ground is established and solved by using the finite difference method. The correctness of the numerical solution is verified by comparing with the existing consolidation model and small- strain analytical solution. Using the numerical solution, the large strain consolidation behaviors of sand-drained ground are investigated. The analyses show that the well resistance of drains can …

Model Tests Of Large-Diameter Single Pile Under Horizontal Cyclic Loading In Sand, Ji-Meng Zhang, Chen-Rong Zhang, Kai Zhang

Rock and Soil Mechanics

A series of 1g model tests was carried out using a motor servo horizontal cyclic loading equipment to study the stiffness and cumulative displacement of the large-diameter single pile in sand under horizontal cyclic loading. The test results indicated that the residual displacement generated by one loading and unloading cycle is about 80% of the peak displacement. As the number of cycles increases, the area of the cyclic loading hysteresis curve gradually decreases, indicating that the behavior of soil around the pile changes from elastoplastic to elastic stage. The secant stiffness of the hysteretic curve increases firstly and then decreases …

Bearing Behavior And Accumulated Rotation Of Modified Suction Caisson (Msc) In Saturated Sand Under Cyclic Loading, Da-Yong Li, Jing-Rui Zhang, Yu-Kun Zhang, Yu-Feng Gao, Jun-Wei Liu

Rock and Soil Mechanics

Modified suction caisson is a new type of suction foundation for offshore wind power engineering. Model tests were carried out to investigate the variation of cumulative rotation angle and its influencing factors of the regular suction caisson (RSC) and modified suction caisson (MSC) under horizontal cyclic loading. The cyclic loading mode includes one-way cyclic loading and variable-amplitude cyclic loading. The experimental results showed that the cumulative rotation angle of the RSC and MSC under horizontal cyclic loading mainly occurs within the first 200 loading cycles. The cumulative rotation angle was found to increase with the increase of cyclic loading amplitude …

Analysis Of Deformation Mechanism Of Soft Soil Reinforcement By Vacuum Preloading, Li-Wen Hu, Zhi-Jun Liu

Rock and Soil Mechanics

Based on the changes of total stress and pore water pressure in the spring model, the mechanism of vacuum preloading consolidation is studied by theoretically discussing the consolidation behavior of soil in vertical and horizontal directions with different boundary conditions. The variation of effective stress and development of deformation are analyzed for the soil under vacuum preloading under stress paths of K0 consolidation and isotropic consolidation based on the boundary conditions, respectively. Meanwhile, the theoretical earth pressure coefficient (K0MC) at rest for soft soil is deduced based on modified Cam-clay model. With engineering applications, the correctness and effectiveness of the …

Surface Tilt Deformation Of Soil Landslides Based On Laboratory And Field Tests, Ji-Ren Xie, Shi-Fan Qiao, Peng-Kun Yu, Taro Uchimura, Gong-Hui Wang, Yao Jiang, Zheng Fang, Jing-Li Tian

Rock and Soil Mechanics

In recent years, surface tilt deformation of soil landslides has become an important indicator of landslide monitoring and early warning, but few studies have been done on the relationship between the slope surface tilt deformation and development characteristics of landslides. In this paper, a series of rainfall model tests combined with field tests was carried out to explore the relationship between the displacement and tilt deformation of slope surface in the process of landslide disaster evolution. A landslide warning method based on the curve of slope surface tilt deformation with time was established. The test results showed that the surface …

Field Model Test On Failure Mechanism Of Artificial Cut-Slope Rainfall In Southern Jiangxi, Li Wang, Gao Li, Yong Chen, Jian-Min Tan, Shi-Mei Wang, Fei Guo

Rock and Soil Mechanics

Geological disasters such as landslides occur frequently in southern Jiangxi, mostly induced by rainfall and artificial slope cutting. Physical model tests, especially field model tests, are considered effective to reveal the mechanism of landslides. The case on a cutting slope featured with weathered metamorphic rock in southern Jiangxi is investigated, in which a self-designed rainfall simulation system is applied. The alignment of field instrumentation includes four boreholes for measuring water content as well as pore pressure and two monitoring points for displacement. An artificial rainfall was carried out on the site. The ground response in terms of water content of …

Finite Element Numerical Modeling And Parametric Study Of Geosynthetic Reinforced Pile-Supported Embankments, Abdallah Ikbarieh

LSU Master's Theses

This study directed at investigating the performance of the pile-supported embankment system utilizing a geosynthetic reinforced load transfer platform (GRLTP) using Finite Element numerical modeling. A 2D Finite Element Modeling (FEM) methodology was first developed using PLAXIS 2D 2021 computer software and verified by well-documented case studies in the literature of this system. Second, a performance prediction was made for a field case study of the Amite River Project near French Settlement, which is located along Route LA 16 Livingston Parish in Louisiana State. A comprehensive FEM parametric study was then carried out to evaluate the performance of the system …

Performance Of Single And Grouped Helical Piles Under Strong Earthquake Shaking, Abdelrahman F.F. Aly

Electronic Thesis and Dissertation Repository

Full-scale shaking table testing was conducted to evaluate the seismic performance of single and grouped helical piles. Eight circular and one square helical piles with different properties as well as one driven circular pile were installed in dry sand enclosed in a laminar soil shear box that was situated on the shaking table. Dynamic properties of sand bed and its natural frequency, as well as the natural frequencies of single and grouped helical pile-soil systems were evaluated from the collected data during different shaking events. The effects of different pile configurations as well as successive shakings on the characteristics of …

Comportamiento De Los Distintos Sistemas Constructivos Para Dos Sótanos En El Suelo Lacustre De Bogotá, Julián David González Agudelo, José Luis Sierra Lozada

Ingeniería Civil

El proyecto, cuenta con una detallada investigación, en la que se comparan procesos constructivos para sótanos, y la manera como se realizan las excavaciones para los mismos, minimizando errores en el proceso y aumentando factores de seguridad con los que se trabaja en los suelos no muy resistentes, como lo es el lacustre de la ciudad de Bogotá. Además, se hace un análisis de tiempos por medio del software de administración de proyectos 'Project', y un análisis de precios unitarios para cada uno de los procesos constructivos que se trabajaron en el presente proyecto de investigación.

El proyecto, se llevó …

Probabilistic Analysis Of The Active Earth Pressure On Earth Retaining Walls For C‑Φ Soils According To The Mazindrani And Ganjali Method, Julian Osorio, Juan Camilo Viviescas, Juan Pablo Osorio

Articles

The determination of the earth pressure coefficients (K) in geotechnical engineering is one of the most critical procedures in designing earth retaining walls. However, most earth pressure theories are made for either clay or sands, where the c-ϕ soils are the least analysed. In this paper, an analysis of the earth pressure for drained mixed soils based in Mazindrani and Ganjali (J Geotech Geoenviron Eng 123:110–112, 1997) theory was carried out. Earth pressure coefficients are generally used in a deterministic way and can represent designs under an inadmissible risk. Therefore, Reliability-based design arises as an essential tool to deal with …

Applications Of Masw And Mhvsr Techniques For Infrastructure Evaluation With A Focus On The Effects Of Different Transformation Techniques And Near-Field Effects On Derived Dispersion Data, Salman Rahimi

Graduate Theses and Dissertations

This dissertation is aimed at understanding two aspects of active surface wave methods to improve the accuracy and reliability of this method. These include (1) the performance of four common wavefield transformation methods for the multichannel analysis of surface wave (MASW) data processing and (2) near-field effects. Toward this end, extensive field measurements were conducted considering different factors affecting these two topics. The MASW and microtremor horizontal to vertical spectral ratio (MHVSR) were then employed to examine their efficiency for infrastructure health monitoring.

Regarding the performance of the four common transformation techniques, it was observed that for sites with a …

Dynamic Soil-Structure Interaction Analysis: Detecting The Reliability Of Modelling The Piles As A Plate Element For A Multistory Building Resting On Deep Foundation, Zeinab Hussein Zein Z.H.Zein, Lina Jaber L. Jaber, Yehya Temsah Y. Temsah

BAU Journal - Science and Technology

The assessment of seismic responses of buildings in dynamic-soil-pile-structure interaction problems has been one of the main interests among researchers in recent decades. Simulating such problems is usually done by two-dimensional models to overcome the difficulties encountered in 3D models. Commonly, piles were represented by plate elements of infinite length, disregarding the soil flowing between piles. Recently, Plaxis – a finite element software- implemented a new feature known as “the embedded pile row” that allows the definition of piles' out of plane spacing in a 2D model. Many researchers proved its validity in accurately simulating the real 3D pile’s behavior. …

Damage Evolution Of Dynamic Characteristics Of Sandstone Under The Sequential Action Of Water-Rock Interaction And Cyclic Loading And Unloading, Hua-Feng Deng, Jing-Cheng Fang, Jian-Lin Li, Guan-Ye Li, Yu Qi, Xiao-Liang Xu

Rock and Soil Mechanics

The rock mass in the hydro-fluctuation belt of the reservoir bank slope is subjected to long-term water-rock interaction and frequent moderate-low intensity reservoir earthquake. The deterioration of the mechanical properties of the rock mass caused by this directly affects the dynamic response and seismic capacity of the reservoir bank slope. Based on this, the settings of the fluctuating zone of the bank slope of the reservoir are simulated, and the water-rock interaction test to simulate the periodic rise and fall of the reservoir water level is designed and carried out. In the course of the test, the cyclic loading and …

Effect Of Sensor Calibration On Moment Tensor Analysis Of Granite Uniaxial Compression, Yi Ren, Shun-Chuan Wu, Yong-Tao Gao, Yi-Xiong Gan

Rock and Soil Mechanics

Moment tensor inversion theory is an effective method to study the rock failure mechanism. However, the inversion results are prone to large errors, which can mislead the understanding of fracture mechanism. In order to achieve a better understanding of the generation process and the mechanism of the rock macro-fracture surface, we perform a location analysis of source events based on the uniaxial compression test of a granite sample, with the help of ultrasonic testing and acoustic emission monitoring. The events near the macro-fracture with small location errors are selected for moment tensor inversion. Then, we use the network calibration method …