Study of the interaction between dry granular flows and rigid barriers with an SPH model          下载免费PDF全文

Xuzhen He  Dongfang Liang  Wei Wu  Guoqing Cai  Chenggang Zhao  Shun Wang 《国际地质力学数值与分析法杂志》2018,42(11):1217-1234

This study uses an incompressible smoothed‐particle hydrodynamics model to investigate the interaction between dry granular material flows and rigid barriers. The primary aim is to summarise some practical guidelines for the design of debris‐resisting barriers. The granular materials are modelled as a rigid‐perfectly plastic material where the plastic flow corresponds to the critical state. The coupled continuity equation and momentum equation are solved by a semi‐implicit algorithm. Compared with flows in controlled flume experiments, the model adequately reproduces both the kinetic of the flows and the impact force under various conditions. Then the numerical simulations are used to study the detailed interaction process. It is illustrated quantitatively that the interaction force consists of two parts, ie, the earth pressure force caused by the weight of the soil and a dynamic force caused by the internal deformation (flowing mass on top of a dead zone). For the estimation of impact load, this study suggests that an increased earth pressure coefficient depending on the Froude number should be incorporated into the hydrostatic model.  相似文献   

Modelling the time‐dependent behaviour of granular material with hypoplasticity          下载免费PDF全文

Shun Wang  Wei Wu  Zhen‐Yu Yin  Chong Peng  Xuzhen He 《国际地质力学数值与分析法杂志》2018,42(12):1331-1345

This paper presents a constitutive model for time‐dependent behaviour of granular material. The model consists of 2 parts representing the inviscid and viscous behaviour of granular materials. The inviscid part is a rate‐independent hypoplastic constitutive model. The viscous part is represented by a rheological model, which contains a high‐order term denoting the strain acceleration. The proposed model is validated by simulating some element tests on granular soils. Our model is able to model not only the non‐isotach behaviour but also the 3 creep stages, namely, primary, secondary, and tertiary creep, in a unified way.  相似文献   

Numerical integration and FE implementation of a hypoplastic constitutive model     

Shun Wang  Wei Wu  Chong Peng  Xuzhen He  Deshan Cui 《Acta Geotechnica》2018,13(6):1265-1281

Hypoplastic constitutive equation based on nonlinear tensor functions possesses a failure surface but no yield surface. In this paper, we consider the numerical integration and FE implementation of a simple hypoplastic constitutive equation. The accuracy of several integration methods, including implicit and explicit methods, is examined by performing a set of triaxial compression tests. Adaptive explicit schemes show the best performance. In addition, the stress drift away from the failure surface is corrected with a predictor-corrector scheme, which is verified by two boundary value problems, i.e. rigid footing tests and slope stability.  相似文献   

Deep learning for efficient stochastic analysis with spatial variability     

He  Xuzhen  Wang  Fang  Li  Wengui  Sheng  Daichao 《Acta Geotechnica》2022,17(4):1031-1051

Acta Geotechnica - Using machine-learning models as surrogate models is a popular technique to increase the computational efficiency of stochastic analysis. In this technique, a smaller number of...  相似文献   

采用岩心钻机改装成大口径工程钻机应注意的问题          下载免费PDF全文

王需贞  陈逸 《探矿工程》1994,(5):23-25,28

岩心钻机改装成大口径工程钻机已取得成功，但在实际使用中，圆锥齿轮经常损坏。分析了影响钻机上圆锥齿轮使用寿命的因素，并提出了改进措施。  相似文献   

Experimental study of particle migration under cyclic loading: effects of load frequency and load magnitude     

Zhang  Sheng  Gao  Feng  He  Xuzhen  Chen  Qilei  Sheng  Daichao 《Acta Geotechnica》2021,16(2):367-380

The study of particle migration in porous media under cyclic loading is the key to understand the mechanism of mud pumping hazard in railway embankments. This paper presents a series of particle migration tests, in which soil particles migrate into an overlying gravel layer under cyclic loading. The results show that the increase in loading frequency and load magnitude leads to more particle migration upwards at a greater rate, implying that the train speed and axle loads affect the extent of mud pumping. The slurry turbidity in the gravel layer increases to a steady state value with time. Soil particles smaller than 5 μm have the potential to diffuse into the entire gravel layer, and larger particles tend to aggregate in the bottom layer of the gravel. The backward erosion gradually develops deeper into the soil layer, and there is a maximum erosion depth associated with each load frequency and load magnitude. As for the mechanism, the pore water pressure oscillates because of liquid sloshing. Its amplitude is much larger in the gravel layer than that in the soil layer due to their difference in permeability. The axial hydraulic gradient acts as a pumping effect to stimulate the migration of soil particles. Increasing load frequency is conducive to the generation of a stronger pumping effect at the gravel–soil interface. Increasing load magnitude does impact not only the extent of pumping effect, but also the development of an interlayer which plays an important role in promoting particle migration.

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