The Thick Sandstone Roof Displacement Distribution Of The Stress Field And The Applied Research

In the actual engineering conditions in Xin ji coal mine210108that has thick roofof sandstone, we adopt complicated study methods such as theoretical analysis,numerical simulation and combination of field measurement to study about miningroof stress distribution of the displacement field in the condition.Through reading literatures to acquire a certain amount of theoretical analysismethods, on-site investigation such as the engineering geology, we decide to usenumerical simulation methods and field trials as the main analytical methods.Using the numerical simulation software FLAC3D, depending on the roof’sthickness and the difference of lithologies, we established five kinds of computingmodels, obtained distribution characteristics under different conditions of stress roofwith roof vertical displacement field, face strike, dip direction distance. We get theconclusion roof thickness and lithology have great influences on stress anddisplacement fields though summarizing the differences and the similarities of the roofdisplacement field distribution of the stress in different environment.In the conditions of thick sandstone roof, Gob roof has the minimum surfacedeformation, the three principal stress of the roof are all in the tensile stress range, thethird principal stress has the maximum principal tensile stress, vertical displacementgradient decay slowly and it has a large and highly fractured zone and caving zone.The thickness of roof rock and lithologies affect mining sphere. In this condition,mining influence the leading and lagging working roof significantly.According to the site, though the installation of multiple position extensometers toobserve the displacement value in the mining process, analyzing data’s throughdatabase software, we get the distribution of the displacement of thick sandstone roofwhich is according with the numerical simulation results and it verified the result’sreasonable of the numerical simulation.By numerical simulation、field measurement and the results of its applied research,we can draw Gob height，distribution of "three zones", high pumping Lane reasonablehorizon identified pillars remained close to the roadway width can affect the coal seam.So it provides the basis for our mining.