| It is an urgent scientifical problem to be solved for safe and high effective coal mining to control the deformation of soft rock roadway subject to the effect of water. Because water can make the actual stress be bigger than the apparent stress which results in faster convergence speed and larger deformation of surrounding rock, the rheological property of surrounding rock is more obvious. Thus, it threats the safety of coal mining seriously. Therefore, it is rather significant to explore the deformation mechanics and the deformation controlling theory of soft rock subjected to the influence of water. For this reason, the deformation mechanism and the controlling method for soft rock tunnel are deeply studied on the basis of former researchers'achievements.The main researches and achievements are as follows:(1) For study the water's contribution to mechanical property and elastic parameter of the soft rock, some soaking tests under different condition are conducted. The results of these tests not only can provide some reasonable mechanical parameters and fully stress-strain curve but also can make us understand the deformation mechanism more deeply and visually.(2) The effects of pore water pressure on creep characteristics of soft rock are studied. Triaxial creep experimentation for soft rock with water has been processed with SJ-1B device which focus on the pore water pressure on the impact of soft rock creep. The results show that the pore pressure is a dramatic factor which can influence the creeping of soft rock. The existence of pore pressure lowers the initial and maximum creep deformation. The pore pressure also can change the damage shape of the rock from tensility to brittleness.(3) According to the laboratory test results, the improved K-B model is selected to describe rock creep. In order to solve the initial problem used by normal square method, the code compiled with MATLAB based on least square optimization pattern search method for model parameter identification, has achieved the desired results.(4) Based on the FLAC3D, this article exploited a code which is called K-B model, and embedded it into the FLAC3D Creep Model Library. Comparing the results of laboratory experiments and simulation results, it is verified the results are in good agreement.(5) In order to study the losing stability rule of soft-rock tunnel which is under water-rock interaction, this article established the model which consider stress field and seepage flow field of rock body. Then we deduced the finite difference scheme and conducted simulation with FLAC3D software. Finally, the deformation mechanism of the soft rock tunnel was achieved.(6) The complexity of the soft rock tunnel deformation and destabilization determine the multiplicity of the soft rock tunnel support format. According to the soft rock's environment and instability mechanism of roadway, some tunnel support schemes were designed, which can be used as a primary guidance for other soft rock support engineering.(7) The research indicated that instability mechanism of ventilation roadway in the sixth mining area of Hong Miao Coal Mine lies in the tectonic stress mechanism and the hydraulics mechanism combined action. Based on the support schemes proposed above, a specific support method was put forward for the roadway and the field test was also carried out. The results show that this scheme has an ideal support effect. The feasibility of the proposed schemes was verified.
|
PDF Full Text Request