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Surficial stability analysis of soil slope under seepage based on a novel failure mode

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Frontiers of Structural and Civil Engineering 2021年第3期15卷 712-726页

作者： Jifeng LIAN Jiujiang WU School of Emergency Science Xihua UniversityChengdu610039China Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province Southwest University of Science and TechnologyMianyang621010China College of Civil Engineering and Architecture Wenzhou UniversityWenzhou325035China

Normally,the edge effects of surficial landslides are not considered in the infinite slope method for surficial stability analysis of soil slopes.In this study,the limit stress state and discrimination equation of an infinite slope under saturated seepage flow were analyzed based on the Mohr-Coulomb strength criterion.Therefore,a novel failure mode involving three sliding zones(upper tension zone,middle shear sliding zone,and lower compression zone)was proposed.Accordingly,based on the limit equilibrium analysis,a semi-analytical framework considering the edge effect for the surficial stability of a soil slope under downslope seepage was established.Subsequently,the new failure mode was verified via a numerical finite element analysis based on the reduced strength theory with ABAQUS and some simplified methods using SLIDE software.The results obtained by the new failure mode agree well with those obtained by the numerical analysis and traditional simplified methods,and can be efficiently used to assess the surficial stability of soil slopes under rainwater seepage.Finally,an evaluation of the infinite slope method was performed using the semi-analytical method proposed in this study.The results show that the infinite slope tends to be conservative because the edge effect is neglected,particularly when the ratio of surficial slope length to depth is relatively small.

关键词： soil slope seepage surficial failure mode stress state edge effects

Effectiveness of Fiber Bragg Grating monitoring in the centrifugal model test of soil slope under rainfall conditions

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Journal of Mountain Science 2017年第5期14卷 936-947页

作者： LI Long-qi JU Neng-pan GUO Yong-xing State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Chengdu 610059 China College of Environment and Civil Engineering Chengdu University of Technology Chengdu 610059 China School of Machinery and Automation Wuhan University of Science and Technology Wuhan 430081 China

Centrifugal model testsare playing an increasingly importantrolein investigating slope characteristics under rainfall conditions. However, conventional electronic transducers usually fail during centrifugal model tests because of the impacts of limitedtest space, high centrifugal force, and presence of water, with the result that limited valid data is obtained. In this study, Fiber Bragg Grating(FBG) sensing technology is employed in the design and development of displacement gauge, an anchor force gauge and an anti-slide pile moment gauge for use on centrifugal model slopes with and without a retaining structure. The two model slopes were installed and monitored at a centrifugal acceleration of 100 g. The test results show that the sensors developed succeed in capturing the deformation and retaining structure mechanical response of the model slopes during and after rainfall. The deformation curvefor the slope without retaining structure shows a steepresponse that turns gradualfor the slope with retaining structure. Importantly, for the slope with the retaining structure, results suggest that more attention be paid to increase of anchor force and antislide pile moment during rainfall. This study verifies the effectiveness of FBG sensing technology in centrifuge research and presents a new and innovative method for slope model testing under rainfall conditions.

关键词： Fiber Bragg Grating sensing technology Centrifugal model test soil slope Rainfall conditions slope displacement

STRUCTURAL DAMAGE MODEL OF UNSATURATED EXPANSIVE soil AND ITS APPLICATION IN MULTI-FIELD COUPLE ANALYSIS ON EXPANSIVE soil slope

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Applied Mathematics and Mechanics(English Edition) 2006年第7期27卷 891-900页

作者：卢再华陈正汉方祥位郭剑峰周海清 Logistic Engineering University Chongqing 400041 P. R. China Navy University of Engineering Wuhan 430033 P. R. China Key Laboratory for the Exploitation of Southwestern Resources and the Environmental Disaster Control Engineering Ministry of EducationChongqing University Chongqing 400044 P. R. China

Focused on the sensitivity to climate change and the special mechanical characteristics of undisturbed expansive soil, an elasto-plastic damage constitutive model was proposed based on the mechanics of unsaturated soil and the mechanics of damage. Undisturbed expansive soil was considered as a compound of non-damaged part and damaged part. The behavior of the non-damaged part was described using non-linear constitutive model of unsaturated soil. The property of the damaged part was described using a damage evolution equation and two yield surfaces, i.e., loading yield （LY） and shear yield （SY）. Furthermore, a consolidation model for unsaturated undisturbed expansive soil was established and a FEM program named UESEPDC was designed. Numerical analysis on solid-liquid-gas tri-phases and multi-field couple problem was conducted for four stages and fields of stress, displacement, pore water pressure, pore air pressure, water content, suction, and the damage region as well as plastic region in an expansive soil slope were obtained.

关键词： unsaturated expansive soil elasto-plastic damage constitutive model consolidation soil slope raining evaporating numerical analysis

Enzyme-Induced Carbonate Precipitation for the Protection of Earthen Dikes and Embankments Under Surface Runoff: Laboratory Investigations

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Journal of Ocean University of China 2022年第2期21卷 306-314页

作者： HE Jia FANG Changhang MAO Xunyu QI Yongshuai ZHOU Yundong KOU Hailei XIAO Liang Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing 210098China College of Engineering Ocean University of ChinaQingdao 266100China Department of Finance and Audit Army Logistics UniversityChongqing 401331China

Earthen structures such as shore protection dikes and river embankments easily suffer from erosion under surface water runoff.This study made experimental efforts to explore the enzyme-induced carbonate precipitation(EICP)method for slope erosion control under surface runoff for earthen structures.The sandy soils were treated by the EICP method for various rounds.Surface characteristics were evaluated by the surface penetration resistance,calcium carbonate content,and surface hard crust thickness of EICP-treated soils.slope runoff erosion experiments were carried out to evaluate the erosion control performances of the EICP treatment.The surface penetration resistance,calcium carbonate content,and surface hard crust thickness were found to significantly increase with the treatment rounds.In the erosion experiments,it was observed that the level of damages decreased and the water flow volume required to trigger the damage increased with more treatments.The increase in the soil slope angle led to more serious surface damages.The amount and rate that the soil particles were eroded from the slope surfaces declined with more EICP treatments,which was consistent with those of visual observations.The preliminary investigations presented in this study have shown the potential of the EICP method for slope erosion control under surface runoff for earthen structures.

关键词： enzyme-induced carbonate precipitation urease erosion soil slope

Explicit Finite Element Simulation for the Large Deformation Failure of the soil slope

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Explicit Finite Element Simulation for the Large Deformation...

The boundary conditions for simulations of a shake-table experiment on the seismic response of 3D slope

2012年海峡两岸破坏科学/材料试验学术会议

作者： HUANG Peng HAO Zhi-ming LI Shun-li Institute of Structural Mechanics China Academy of Engineering Physics

The large deformation failure simulation of the soil slope is an important topic in the computational mechanics field.Due to mesh distortion,the classic implicit finite element method suffers from the difficulties to treat the large deformation involved in the soil slope failure.The explicit finite element method has the better advantage to track the material interfaces and solve the large deformation problems,because this method adopts the explicit time integration algorithm. Based on the Drucker-Prager elastic-plastic constitutive model,the large deformation failure problems for both clay and sand slopes were solved using the explicit finite element method.The simulations presented the slip failure process of the clay slope under gravity,and illustrated the formation and growth of the slip surface.The large flow process of the sand slope was also simulated,and the computed results showed the reposed angle of the sand slope was smaller than the internal friction angle of sand material.This study revealed that different failure modes were appeared in clay and sand slopes under gravity.

关键词： soil slope Large Deformation Explicit Finite Element Method Elastic-plastic Constitutive Model

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Earthquake Engineering and Engineering Vibration 2017年第1期16卷 23-32页

作者： Tang Liang Cong Shengyi Ling Xianzhang Ju Nengpan School of Civil Engineering Harbin Institute of Technology State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology School of Civil Engineering Qingdao Technological University

Boundary conditions can significantly affect a slope＇s behavior under strong earthquakes. To evaluate the importance of boundary conditions for finite element （FE） simulations of a shake-table experiment on the slope response, a validated three-dimensional （3D） nonlinear FE model is presented, and the numerical and experimental results are compared. For that purpose, the robust graphical user-interface ＂slopeSAR＂, based on the open-source computational platform OpenSees, is employed, which simplifies the effort-intensive pre- and post-processing phases. The mesh resolution effect is also addressed. A parametric study is performed to evaluate the influence of boundary conditions on the FE model involving the boundary extent and three types of boundary conditions at the end faces. Generally, variations in the boundary extent produce inconsistent slope deformations. For the two end faces, fixing the y-direction displacement is not appropriate to simulate the shake-table experiment, in which the end walls are rigid and rough. In addition, the influence of the length of the 3D slope＇s top face and the width of the slope play an important role in the difference between two types of boundary conditions at the end faces （fixing the y-direction displacement and fixing the （y, z） direction displacement）. Overall, this study highlights that the assessment of a comparison between a simulation and an experimental result should be performed with due consideration to the effect of the boundary conditions.

关键词： boundary condition dynamic response soil slope nonlinear finite element analysis shake-table experimentearthquake

Determination of a Mathematical Model of Erosion Taking into Account the Intensity of Rainfall and soil slopes from the Global MNT Model

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Engineering（科研） 2022年第7期14卷 274-284页

作者： Eric Flavien Mbiakouo-Djomo Timothée Thierry Odi-Enyegue André Abanda Gilbert Tchemou Ulrich Florin Djiofack-Tiagho Denis Tcheukam-Toko Ngouffo Koukougnang Réné Didier Fokwa Ebénézer Njeugna Department of Rural Engineering FASA University of Dschang Dschang Cameroon Department of Civil Engineering ENSPD University of Douala Douala Cameroon Department of Mechanical Engineering College of Technology University of Buea Buea Cameroon Department of Civil Engineering ENSET Douala Cameroon Laboratory of Mechanics and Modeling of Physical Systems University of Dschang Dschang Cameroon

Our study is being carried out in the Wouri Estuary more precisely in the Nylon area, Douala. This area is influenced by abundant rainfall which promotes the phenomenon of rain erosion. This erosion contributes to the degradation of structures and soils. To better understand and predict this phenomenon of rainfall erosion, we set out to establish a mathematical model that takes into account precipitation and topography. To this end, the data collected in the field and in the laboratory made it possible. First, we graphically modeled the variation of the potential as a function of the intensity of rainfall and the slope of the ground. Next, we identified a mathematical model from cubic spline surface interpolation. Finally, we obtained the mathematical model which makes it possible to evaluate and predict the erosion potential. The results obtained allowed to have an erosion potential of 153.67 t/ha/year with field data and 153.94 t/ha/year with laboratory data. We compared the results obtained with those existing in the literature on the same study site. This comparison made it possible to validate the established mathematical model. This mathematical model is a decision support tool and can predict problems related to water, erosion and the environment.

关键词： Erosion Erosion Potential Mathematical Model Rainfall Intensity soil slope

Development of a GIS-based failure investigation system for highway soil slopes

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Frontiers of Earth Science 2015年第2期9卷 165-178页

作者： Raghav RAMANATHAN Ahmet H. AYDILEK Burak F. TANYU Paul C. Rizzo Associates Inc. 500 Penn Center Blvd. Pittsburgh PA 15235 USA Department of Civil and Environmental Engineering University of Maryland MD 20742 USA Department of Civil Environmental and Infrastructure Engineenng George Mason University Fairfax VA 22030 USA

A framework for preparation of an early warning system was developed for Maryland, using a GIS database and a collective overlay of maps that highlight highway slopes susceptible to soil slides or slope failures in advance through spatial and statistical analysis. Data for existing soil slope failures was collected from geotechnical reports and field visits. A total of 48 slope failures were recorded and analyzed. Six factors, including event precipitation, geological formation, land cover, slope history, slope angle, and elevation were considered to affect highway soil siope stability. The observed trends indicate that precipitation and poor surface or subsurface drainage conditions are principal factors causing slope failures. 96% of the failed slopes have an open drainage section. A majority of the failed slopes lie in regions with relatively high event precipitation （P 〉 200 mm）. 90% of the existing failures are surficial erosion type failures, and only 1 out of the 42 slope failures is deep rotational type failure. More than half of the analyzed slope failures have occurred in regions having low density land cover. 46% of failures are on slopes with slope angles between 20~ and 30~. Influx of more data relating to failed slopes should give rise to more trends, and thus the developed slope management system will aid the state highway engineers in prudential budget allocation and prioritizing different remediation projects based on the literature reviewed on the principles, concepts, techniques, and methodology for slope instability evaluation （Lesh- chinsky et al., 2015）.

关键词： soil slope slope management system geo-graphic information system hazard mapping