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Based on the changes of total stress and pore water pressure in the spring model, the mechanism of vacuum preloading consolidation is studied by theoretically discussing the consolidation behavior of soil in vertical and horizontal directions with different boundary conditions. The variation of effective stress and development of deformation are analyzed for the soil under vacuum preloading under stress paths of K0 consolidation and isotropic consolidation based on the boundary conditions, respectively. Meanwhile, the theoretical earth pressure coefficient (K0MC) at rest for soft soil is deduced based on modified Cam-clay model. With engineering applications, the correctness and effectiveness of the mechanism is confirmed by the application in large area of ground improvement for soft soil and statistical analysis of some engineering cases. It is found that the drainage boundary condition and the scale of treated area have effects on deformation of soil mass. For the middle part of the treated zone under large-area vacuum preloading, the variation of effective stress is not isotropic, but following the pattern of one-dimensional compression. According to the statistic results from some site investigations, one-dimensional compression equation (Cc-Cr method) can be applied to predict the settlement at the center of the treated zone when the one dimensional condition is found in the center of treated zone as the ratio between treated breadth and length of vertical drains larger than 4-5.

During in-situ exploitation of the oil shale, the connectivity of the pore structure of the reservoir directly affects not only the flow behavior and heat transfer efficiency of the heat-carrying medium, but also the diffusion and flow behaviors of the oil and gas. In this study, the T2 spectra of saturated water and bound water in samples from the Fushun oil shale were measured with low-field nuclear magnetic resonance at different final pyrolysis temperatures (23~650℃). NMR pore parameters, including T2 cutoff value of movable fluid, bound fluid porosity, saturated fluid porosity and permeability, were analyzed. The evolution of pore connectivity of the oil shale with final pyrolysis temperature was studied quantitatively. The results demonstrated that final pyrolysis temperature affected the variations of pore connectivity and the permeability of oil shale. The increase of total porosity could be attributed mainly to the increments of movable fluid. These results indicated that increases in final pyrolysis temperature enhanced the permeability and transport of oil and gas, providing a basis for further understanding of the evolution of pore structure in oil shale in-situ pyrolysis.

In order to improve the heat dissipation performance and study the factors affecting the heat dissipation effect of a two-dimensional ordered porous structure, a thermal analysis of the radiator in the power module of a DC charging pile was carried out. Based on the thermal analysis of the grid-type radiator, the square-hole radiator is subjected to a thermal analysis, the heat dissipation performance of the two radiators is compared, and the factors affecting the heat dissipation effect of the square-hole radiator are explored. Research shows that the heat dissipation effect of the square-hole radiator, which represents a twodimensional ordered porous structure, is better than that of the grid-type radiator. The factors affecting the heat dissipation effect of the square-hole radiator are mainly related to the height of the radiator and are positively related to the heat dissipation effect of the radiator.

C6H25Br3N2O3P2, triclinic, P1̅ (No. 2), a = 8.6192(6) Å, b = 10.0012(11) Å, c = 12.8047(8) Å, α = 110.699(8)°, β = 95.859(6)°, γ = 99.141(7)°, V = 1004.36(15) Å3, Z = 2, Rgt(F) = 0.0777, wRref(F2) = 0.1918, T = 293(2) K.