SUMMARY: The interactive method of interface boundary elements (IBEs) and partitioned finite elements (PFEs) is proposed for solving such problems as local continuous/discontinuous deformation (i.e., landslide, concrete cracking, rock mass joints, and internal contraction joints) in concrete dams. The system is divided into continuous displacement bodies and continuous stress joints. The continuous displacement bodies are solved using PFE with the nodal displacements treated as variables, and the rigid displacements in each body and the constraining internal forces on the boundary interface are solved using IBE based on the continuous stress condition and the static force equilibrium condition in each body. Each IBE consists of all interface boundary nodes in a body, and the flexibility matrix is formed using PFE or theoretical analysis. Using this method, a nonlinear iteration procedure is carried out only on the possible discontinuous interface, an approach that greatly improves the computational efficiency. Three numerical examples are used to verify the correctness and validity of the proposed method. © 2014 The Authors. International Journal for Numerical Methods in Engineering published by John Wiley & Sons Ltd.

The stability analysis of rock slopes has been a prominent topic in the field of rock mechanics, primarily due to the widespread occurrence of discontinuous structural planes in rock masses. Based on this complex characteristic of rock slopes, this paper proposes a novel numerical method, the Partitioned-Rigid-Element and Interface-Element (PRE-IE) method. In the PRE-IE method, the structure is modeled as several rigid bodies and discontinuous structural planes, which are, respectively, divided into partitioned rigid elements and interface elements. Taking the contact force of node pairs and the displacement of the rigid body centroid as mixed variables, according to the principle of minimum potential energy, the governing equations of PRE-IE can be established using the Lagrange multiplier method and then solved using the nonlinear contact iterative method and the incremental method. A classic case study demonstrates that using the failure of all contact node pairs as the criterion for slope failure is appropriate. This criterion is objective and avoids the potential impact of personal bias on safety factor calculations. Two numerical examples of differently shaped slopes are provided to verify the correctness and validity of the PRE-IE method. By comparing the safety factor calculated using the PRE-IE method with those obtained from other different methods, as well as comparing the computational time, it is shown that the PRE-IE method, in combination with the SRM, can accurately and efficiently analyze the stability problems of rock slopes.

During the long-term operating period, the mechanical parameters of hydraulic structures and foundation deteriorated gradually because of the environmental factors. In order to evaluate the overall safety and durability, these parameters should be calculated by some accurate analysis methods, which are hindered by slow computational efficiency and optimization performance. The improved deep Q-network (DQN) algorithm combined with the deep neural network (DNN) surrogate model was proposed in this paper to ameliorate the above problems. Through the study cases of different zoning in the dam body and the actual engineering foundation, it is shown that the improved DQN algorithm has a good application effect on inversion analysis of material mechanical parameters in this paper.

The method of adding a flexible anti-seepage layer is a way to solve the problem of cracks in upstream surfaces of arch dams. Spraying polyurea as anti-seepage layer has been used in several projects for the crack repairing in china. But there is no technique standard for checking the construction quality in using sprayed polyurea, such as requirements of thickness, material tensile strength, bonding strength, anti-seepage and wear resistance. Taking Xiluodu arch dam as an example, the test in-situ is done to check whether the main requirements for material behavior are reasonable and economic..

A direct algorithm of heat interchange between concrete and water pipes is considered to simulate the cooling effect is presented in this paper. The heat propagated from cooling water pipes to concrete is obtained directly after the internal temperature field of concrete is solved. Then the water temperature along the cooling water pipes can be obtained directly instead of the temperature gradient around the pipes. An example is used to verify the validity of the method. What the mesh density influences the calculation result is also discussed.