Research On The Mechanical Properties Of Inhomogeneous Thick Frozen Wall In Deep Alluvium

Coal is the primary energy in China, in order to satisfy the development of national economy, the needs of coal resource under the deep alluvium become more and more impendent. And these shaft well are inevitably needed through the deep alluvium (400~800m). With the increasing freezing depth and topsoil layer depth, the depth of the frozen wall also increased constantly. But the thick frozen wall formed by multi-coil frozen pipes is still researched as homogeneous material according to the average temperature of frozen wall, there may be some error that may affect the safety of the frozen wall in the deep alluvium.By the physical simulation, numerical simulation and theoretical analysis, as well as the data of engineering measuring, the research on mechanical characteristic of multi-coil thick frozen wall in deep alluvium has been taking on. Combining the condition of deep alluvium and the engineering characteristic of freezing shaft are also taken into consideration, as well as the effect of the heterogeneity of multi-coil thick frozen wall for its stability, the engineering properties of the frozen wall in non-uniform temperature field under high confining pressure had been carried out.The second chapter is based on the elastic-plastic theory, and considering radial delamination of multi-coil thick frozen wall in deep alluvium (radial temperature distributing of frozen wall). On the basis of constitutive relation of deep frozen soil in test measuring, the stress field, carrying capacity and radial deformation characteristic of frozen wall have been researched under the condition of the radial uneven condition. Meanwhile basing on the measured data, the rule of radial distortion was researched, considering the upper and lower side of the working face at different constraints above the limited segment height conditions, so, some references were provided to the design of frozen wall in deep alluvium.The evolution law of temperature field of the multi-coil thick frozen wall in deep alluvium along with the stability of the frozen wall in the direction of the depth of the different layers (layers of sand and clay) were simulated by ANASYS (finite element analysis software), taking on the premise of non-uniform temperature field of the frozen wall into account, to obtain more accurate distribution law of stress field and deformation field, which can provide a useful reference to the design and construction for freezing shaft in deep alluvium.The success of the design and establishment of deep soil and frozen soil multi-purpose simulation systems, and the physical simulation tests of multi-coil thick frozen pipes were carried through the test-bed. At the same time theoretical analysis and numerical simulation results correspond to each other.On the basis of theoretic analysis, numerical simulation, physical simulation and engineering measured the deep alluvium in thick multi- coil wall to freeze time and space design was brought out for multi-coil thick frozen wall of the deep alluvium. This research had important economic value and social value.