基于五阳煤矿7603孤岛工作面工程地质概况,进行现场调研并分析了运输巷掘进过程中出现两帮＂平移＂大变形的机理,得出巷道围岩变形机制是构造应力型（IIA）和重力型机制（IIB）＋弱层走向型机制（IIIBA）＋层理走向型机制（IIICA）＋随机节理型机制（IIIE）的复合变形力学机制;运用变形力学机制转化原理,提出＂携顶底,控两帮＂的支护思路,进而提出了新的支护方案。运用FLAC3D数值模拟对比分析了新方案与原方案的支护效果,新方案塑性区发育较原方案少106.5 m2单位面积;新方案顶底板移近量较原方案减少了65.4%,两帮移近量减少了78.9%,新方案可以有效控制围岩两帮平移大变形。工业性试验表明,运输巷道的顶底板最大移近量约250 mm,两帮最大移近量仅有350 mm,分别比原支护方案减小45.9%和79.2%;两帮锚杆受力在110-160 k N之间,锚索受力值约为300 k N,均在15 d前后趋于稳定,巷道围岩得到了有效控制,能够满足通风和安全生产需要。
The effects of saturation on post-peak mechanical properties and energy features are main focal points for sandstones. To obtain these important attributes, post-peak cyclic loading and unloading tests were conducted on sandstone rock samples under natural and saturated states using the RMT-150B rock mechanics testing system. After successful processing of these tests, comparisons of stress-strain, strength, deformation, damage, and degradation of mechanical properties, wave velocity, and energy features of sandstone were conducted between natural and saturated states. The results show that saturation has evident weakening effects on uniaxial cyclic loading and unloading strength and elastic modulus of post-peak fracture sandstone. With the increase of post-peak loading and unloading period, the increases in amplitude of peak axial, lateral, and volumetric strains are all enhanced at approximately constant speed under the natural state. The increase in amplitude of axial peak strain is also enhanced at approximately constant speed, while the amplitudes of lateral and volumetric peak strains increase significantly under the saturated state. Compared with the natural state, the increase in amplitude of saturated samples＇ peak lateral and volumetric strains, and the post-peak cyclic loading and unloading period all conform to the linearly increasing relationship. Under natural and saturated states, the damage factor （the plastic shear strain） of each rock sample gradually increases with the increase of post-peak cyclic loading and unloading period, and the crack damage stress of each rock sample declines rapidly at first and tends to reach a constant value later with the increase in plastic shear strain. Under natural and saturated states, the wave velocities of rock samples all decrease in the process of post-peak cyclic loading and unloading with the increase in plastic shear strain. The wave velocities of rock samples and plastic shear strain conform to the exponential relationship with a constant. Saturati
