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Yin K.-L.,Wuhan University | Liu Y.-L.,Wuhan University | Wang Y.,Wuhan University | Jiang Z.-B.,Changjiang Scientific Research Institute
Diqiu Kexue - Zhongguo Dizhi Daxue Xuebao/Earth Science - Journal of China University of Geosciences

The impoundments of Three Gorge Reservoir have obviously intensified the reservoir bank landslide deformation since 2003. Landslide deformation can cause not only damages, but also evokes great surge once high-speed landslide sliding into reservoir, which is a potential hazard far worse than landslide itself. Owing to the reservoir impoundment, Qianjiangping landslide in Three Gorges Reservoir Area (TGRA) occurred on July 13, 2003. The highest height of landslide-induced surge reached 39 meters which resulted in wave spreading more than 30 kilometers far away along the channel, causing casualties and property losses. In order to study the characteristics and propagation law of landslide-induced surge, based on the major scientific project in TGRA, this paper presenta comprehensive researches on landslide surge hazard in TGRA through large laboratory physical model experiments. Through the statistical analysis of geological data about the potential landslides in TGRA, adopting the orthogonal experimental design method, we formulated the experiment scheme which included landslide scale, speed entering into the water, sliding plane obliquity, water depth, and slope angle. Besides, we took the channel of Baishuihe landslide in TGRA as prototype, established the river physical model in map scale 1:200, and thus developed landslide surge three-dimensional physical model experiment by adopting the experimental control system and measurement system. According to the careful physical model experiments, we obtained reliable experimental data of landslide surge. Based on the morphological changes of landslide surge, we confirmed the concept of head wave. Then based on the classical landslide surge formulas proposed by Noda and Pan Jiazheng, by analyzing the measured data, we deduced the landslide surge calculation formulas in TGRA. At last, taking Baishuihe landslide being in deformation as an example, these formulas were used to forecast the maximum head wave height and the decay law of landslide surge along the channel. Source

Fu D.-G.,Chinese Ministry of Water Resources | Liu J.-P.,Wuhan University | Zhou L.-M.,Chinese Ministry of Water Resources | Xu H.,Changjiang Scientific Research Institute | And 2 more authors.
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering

Obtaining shear-wave velocity and thickness of soft interlayer with higher precision is always one of the difficulties in inversion of Rayleigh-wave dispersion curve, and it is not obviously improved when only depending on the improved algorithm and multimode inversion for low-sensitivity soft interlayer. The improved algorithm and combination of multimode and nonlinear Bayes' theorem are adopted to invert low-sensitivity soft interlayer. The damping inertia weight and chaos are added into the particle swarm optimization as improved algorithm. However, the improved algorithm does not solve the problem with low-sensitivity soft interlayer models. To analyze and evaluate the factors affecting the accuracy of inversion from the perspective of the inversion solution, the unbiased Metropolis-Hastings sampling (MHS) method is used for numerical integration posterior probability, and the rotation of parameters is used to improve the efficiency of sampling. The obtained integral 1D and mixed marginal probability distributions and correlation sufficiend matrix of parameters reflect the uncertainty and parameter inversion solution for correlation and other information. To solve the problem of low-curacy inversion of low-sensitivity soft interlayer, the Bayesian information criterion (BIC) is employed to determine the optimal parameters of the model. The optimal model agrees with the theoretical one. Applying the nonlinear Bayesian inversion method and BIC to invert the measured data of seepage prevention wall, the obtained inversion profiles are also in good agreement with the structure of the known seepage prevention wall. ©, 2015, Chinese Society of Civil Engineering. All right reserved. Source

Wen S.-L.,Changjiang Scientific Research Institute | Chai H.-T.,Changjiang Scientific Research Institute
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering

Through centrifugal model tests, 95 g centrifugal acceleration is applied for studing the effects of loading points on horizontal bearing capacity, displacement, moment and inclination of piles at different loading points. After comparative analysis of two groups of model tests with horizontal loading point h=159 and h=135 mm, it is found that the horizontal bearing capacity of the piles decreases with the increase of the horizontal loading point under the same displacement conditions, and the pile foundation moment, inclination and displacement increase with the increase of the horizontal loading point under the same loading conditions. Source

Xu D.-D.,CAS Wuhan Institute of Rock and Soil Mechanics | Zheng H.,CAS Wuhan Institute of Rock and Soil Mechanics | Wu A.-Q.,Changjiang Scientific Research Institute | Lu B.,Changjiang Scientific Research Institute
Jisuan Lixue Xuebao/Chinese Journal of Computational Mechanics

First, fluid-solid coupling technology of the discrete element method is utilized to simulate the seepage field in fractured rock, and the seepage pressure acting on the removable rock block is obtained. Then, effect of seepage to the dynamic stability of the rock block based on the block theory is studied, and the contrast curve of the dynamic safety factors under the condition of whether the seepage effect is considered is obtained. The result shows that, dynamic stability of the block is decreased by the seepage effect. Meanwhile, a procedure of block stability analysis based on the parameter sensitivity is developed. Having been applied to the practical slope engineering, the procedure can be employed to conduct fast stability of blocks the different value combinations of cohesion and friction angle. The applications show that it is simple, convenient, and exact. Source

Chen X.,Changjiang Scientific Research Institute | Yan J.,Changjiang Scientific Research Institute | Yang H.,Changjiang Scientific Research Institute
Applied Mechanics and Materials

Concrete cracking sensitivity made from different aggregates was compared with employment of advanced temperature and stress test machine by tracking thermal and stress development of concrete with age and elements distribution in interfacial transition zone of each concrete was explored by SEM and EDS. Test results indicated that compressive strength of concrete made from basalt and limestone was greater than diorite and natural aggregate and crack resistance of concrete based on cracking sensitivity comparison in terms of cracking temperature varying from minus 0.3°C to minus 2.5°C as diorite, basalt, limestone and natural aggregate. Elements Ca and Mg were apparently accumulated in vicinity of ITZ and some reaction between limestone and cement matrix might have taken place which blurred the boundary between aggregates and cement matrix. © (2012) Trans Tech Publications, Switzerland. Source

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