In Miyi County of Sichuan Province of China, landslides are the most common type of waste dump failure, resulting from poorly compacted waste rock dump on weak soil. A waste dump failure on a soft, ...gently dipping foundation is examined in terms of the geological conditions, failure characteristics, movement processes and deposit forms, including the long run-out feature of the landslide. The waste dump failure and the subsequent deformation to the foundation are caused by an increase in pore water pressure and developed through the soft foundation underlying the heavy waste. The landslide run-out distance is influenced by the liquefiable silty clay layer. In this study, the landslide was triggered by the heavy load of waste rocks on top of a soft foundation of low-bearing capacity. The increased pore pressure in the foundation could not be released, which caused deformation of the foundation and triggered a landslide. The stability evolution is also researched in this study. In this study area: (1) the landslide mass is accelerated by the liquefaction of the saturated and water-rich silty clay layer, and the plastic deformation of the foundation caused by the collapsed waste dump; (2) the shear strength is strongly influenced by the water content; (3) when a waste dump is constructed on top of a water-sensitive gently dipping ground, it is important to provide drainage to dissipate pore water pressure; and (4) considering low factors of safety during heavy rains, secondary landslide is possible in the event of heavy rain and earthquake, indicating that heavy rainfall is the leading cause of the waste dump failure.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Introduction: With the development of the new energy vehicle industry, the research aims to improve the energy utilization efficiency of electric vehicles by optimizing their composite power supply ...parameters. Methods: An optimization model based on non-dominated sorting genetic algorithm II was designed to optimize the parameters of liquid cooling structure of vehicle energy storage battery. The objective function and constraint conditions in the optimization process were defined to maximize the heat dissipation performance of the battery by establishing the heat transfer and hydrodynamic model of the electrolyzer. Results: The results showed that the optimization method had excellent performance on multiple evaluation indicators, the material degradation rate after optimization was reduced by 42%, the corrosion rate was reduced by 36%, and the battery life was increased by 17%. The optimization method ensured the maximum temperature control for the safe operation of the lithium-ion battery pack. The temperature of the battery pack was effectively controlled. The temperature difference was kept within 5°C, preventing the battery from overheating and extending its service life. Discussion: The proposed liquid cooling structure design can effectively manage and disperse the heat generated by the battery. This method provides a new idea for the optimization of the energy efficiency of the hybrid power system. This paper provides a new way for the efficient thermal management of the automotive power battery.
Changes in groundwater are an important factor affecting slope stability. In this study, the finite-element-based limit equilibrium method (FELE), which does not require any predetermined ...assumptions, is improved to include groundwater. The seepage force in the improved FELE is directly regarded as a body force and can be transformed into the equivalent nodal force. Moreover, a practical technique of employing the signed distance function is used to represent the groundwater level, making the improved FELE insensitive to the mesh. An analysis of a benchmark slope is performed to validate the effectiveness of the improve FELE, and the results show that the seepage force has a significant influence on the stability of the slope. Moreover, a case study of a deforming bank slope from the Three Gorges Reservoir is analyzed by the improved FELE to study the relationships between the deformation and changes in the phreatic lines within the sliding body.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Wujiang landslide, which is an ancient landslide, has a total volume of approximately 1.327×107m3. Its downstream boundary is approximately 300 and 590m away from the new dam and axis of the dam, ...respectively, while the upstream boundary is approximately 1000m away from the dam. The relative relief of the landslide ranges from 380 to 480m with moderately steep terrain and well-developed gullies. In this study, we have investigated the geotechnical characteristics of the landslide and analyzed its formation conditions and evolution process. We conclude that the landslide can be classified into the bedrock crack-bedding slip mode and is an ancient landslide where creep deformation still exists although it has undergone repeated sliding evolution. We have further analyzed its deformation characteristics: the landslide is currently in a slow creep deformation state, with the deformation larger at the leading edge and smaller at the trailing edge. Hence, the disintegration of the superficial part or the slip of the shallow-upper part of the landslide is likely to occur. Conversely, the possibility of the whole slope sliding down is relatively low. Finally, based on Morgenstern-Price assumptions, we have developed a rigorous three-dimensional analysis method that can analyze the stability and identify the dominant sliding direction of the landslide during the impoundment of the reservoir.
•Formation conditions and evolution of Wujiang Landslide process are investigated.•Deformation characteristics of Wujiang Landslide are described.•A new stability analysis method is proposed.•Its stability are analyzed and its dominant sliding direction is identified during impoundment of reservoir.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The study area, Woshaxi landslide, is 400 m long and 700 m wide, with an average thickness of approximately 15 m and a volume of 4.2 × 10
6
m
3
. The Woshaxi landslide, which is located on the ...Qinggan River, a tributary of the Yangtze River in the Three Gorges reservoir area, is just 1.5 km from the Qianjiangping landslide. The Qianjiangping landslide following the Three Gorges reservoir impoundment was caused by the combined effects of rainfall and reservoir water-level fluctuation. In this study, the Woshaxi landslide’s deformation characteristics and mechanism are investigated based on deformation monitoring data and a geological survey during the initial impoundment period of the Three Gorges reservoir. Furthermore, based on the characteristics of the combined effects of reservoir water level fluctuation and rainfall in the Three Gorges reservoir area, the stability evolution behavior of the Woshaxi landslide during the initial impoundment period of the Three Gorges reservoir is investigated.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A three-node triangular element fitted to numerical manifold method with continuous nodal stress, called Trig3-CNS （NMM） element, was recently proposed for linear elastic continuous problems and ...linear elastic simple crack problems. The Trig3-CNS （NMM） element can be considered as a development of both the Trig3-CNS element and the numerical manifold method （NMM）. Inheriting all the advantages of Trig3-CNS element, calculations using Trig3-CNS （NMM） element can obtain higher accuracy than Trig3 element without extra degrees of freedom （DOFs） and yield continuous nodal stress without stress smoothing. Inheriting all the advantages of NMM, Trig3-CNS （NMM） element can conveniently treat crack problems without deploying conforming mathematical mesh. In this paper, complex problems such as a crucifix crack and a star-shaped crack with many branches are studied to exhibit the advantageous features of the Trig3-CNS （NMM） element. Numerical results show that the Trig3-CNS （NMM） element is prominent in modeling complex crack problems.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
To avoid disadvantages caused by rotational degrees of freedom in the original Discontinuous Deformation Analysis (DDA), a new block displacement mode is defined within a time step, where ...displacements of all the block vertices are taken as the degrees of freedom. An individual virtual element space
(Ω) is defined for a block to illustrate displacement of the block using the Virtual Element Method (VEM). Based on VEM theory, the total potential energy of the block system in DDA is formulated and minimized to obtain the global equilibrium equations. At the end of a time step, the vertex coordinates are updated by adding their incremental displacement to their previous coordinates. In the new method, no explicit expression for the displacement
is required, and all numerical integrations can be easily computed. Four numerical examples originally designed by Shi are analyzed, verifying the effectiveness and precision of the proposed method.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Using the movability analysis in block theory, one can easily determine all movable blocks. However, only for a movable block with no more than two structural surfaces, called the statically ...determinate block, can the factor of safety be determined by the static analysis, which limits more extensive application of key block theory. In order to analyze general movable blocks with multiple structural planes, an optimization model for solving the safety factor of blocks is built in this paper. In the model, the safety factor as well as the normal stress on the slip surface is taken as independent variables; and the objective function is specified as the safety factor alone. The statically admissible conditions include the system of equilibrium equations, non-negativity of both normal stress on the slip surface and thrust inside the block. Since the objective function is linear and the constraint functions are polynomials of no more than degree-2, it is weak in nonlinearity and can be solved by those conventional optimization techniques, and disadvantages of the conventional block theory are overcome. After some typical examples are tested, the stability of the left bank rock slope of Jinping-I Hydropower Station is conducted in detail, and the stability evolution due to excavation is systematically studied by this method.
•A procedure is proposed for evaluating stability of statically indeterminate blocks.•An optimization model is built for yielding reasonable forces in 3D blocks.•A hydraulic engineering example is analyzed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The contact is a typical non-linear problem that exists in various projects. For traditional three-node triangular mesh and four-node quadrilateral mesh, the accuracy and convergence of the ...calculation results are affected by the quality of the mesh. The test space and trial space in the virtual element method (VEM) do not need to be accurately calculated, avoiding mesh dependence. In this paper, the formulation of linear elasticity and the formulation of the frictionless node-to-segment (NTS) contact model
via
VEM are shown. There are four numerical simulations. The sensitivity of the virtual element method to mesh distortion is studied in the first numerical simulation. The exactness and convergence of the algorithm are investigated by the second numerical example. The second numerical example simultaneously explores the penalty factor’s effect on the results. The third example investigated the impact of mesh shape and number of Voronoi mesh elements on the results by comparing normal contact stresses. The fourth numerical example studies the application of the method to engineering. Those numerical examples show that the virtual element method is insensitive to mesh distortion and could solve the joint contact in engineering.
PDF
