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Our research targets a subway foundation pit construction project in Nanning, a city in southwestern China. The foundation pit was excavated in the water-rich round gravel stratum. The theoretical calculation was combined with finite-element analysis, which is based on drag coefficient method, to derive the relevant seepage parameters of the stratum. The complex seepage surface was solved through the meshing of virtual grids with fixed nodes. The 3D seepage field around the ground-connecting wall in the pit (hereinafter referred to as the wall) was investigated through finite-element analysis on midas GTS NX. In this way, the author identified the features and law of soil seepage around the wall in the water-rich gravel stratum. The results show that the middle and lower part of the wall were within the sand layer and the gravel layer, both of which are strongly permeable; the seepage rate around the wall peaked in the middle of the wall (0.156 m/sec); there was an obvious seepage effect in the pit; the waterrich gravel stratum had greater seepage water inflow than any other stratum; the pore water migration features could be described accurately by the seepage control equation of the heterogeneous anisotropic porous medium. [ABSTRACT FROM AUTHOR]

Considering the importance of friction coefficient in bearing performance and the good properties of MoS2, this paper designs an innovative friction sliding isolation bearing with MoS2 as the lubricating material. The relationship between the friction coefficient and the compressive stress was determined by fitting the results of a loading test, and the feasibility of the material was proved through a shaking table test on a five-layer concrete frame model. Based on the energy dissipation theory, the seismic behavior of the proposed friction sliding isolation structure was simulated on MATLAB/Simulink. The simulation results show that the entire structure had little displacement, despite the slight slippage of the isolation layer, under the simulated earthquake wave. The energy response at different friction coefficients shows that the total seismic energy input of the system increased with the friction coefficient. The change of the total seismic input was not obvious when the friction was up to 0.15. The research findings shed new light on the application of isolation devices in practical engineering. [ABSTRACT FROM AUTHOR]