基于侧压力差异性的深部巷道多场耦合规律分析

Multi-field coupling law analysis of deep roadway based on lateral pressure difference

为综合分析某深部巷道在侧压力差异性下围岩能量场、应力场及位移场之间的影响特征,为后续施工提供理论指导,考虑4种侧压力系数(κ为0.6、0.9、1.2和1.5),采用三维建模软件Rhino进行基本网格建模,再映射至颗粒流离散元软件PFC3D进行数值模拟分析。结果表明,1)κ的差异性使围岩应力场发生变化,应力场带动颗粒的运动状态改变,从而进一步影响系统能量场:当κ从0.6增至1.5时,动能增至原来的3.8倍,应变能增至原来的2.6倍;开挖完成后同水平κ下动能衰减至初始值的2%~23%,应变能则衰减至初始值的80%~90%。2)根据κ对围岩应力场影响程度的不同,将围岩分为浅、中、深3部分,其与开挖巷道的扰动区相对应,应力场变化呈现按照深部岩体、中部岩体、浅部岩体依次增大的现象;随着κ的增大,围岩应力场中主导应力改变,体现出拱腰应力变化幅度大于拱顶与拱底的现象,其最大绝对变化量为52%。3)位移场与应力场变化相对应,当κ的差异性导致应力场发生变化时,围岩主导应力状态将会不同,具体表现为随κ的增大,拱顶、拱底竖向最大位移减小及云图中水平扰动区范围增大。

This paper investigates four types of lateral pressure coefficients(κ: 0.6, 0.9, 1.2, 1.5) from measured data to comprehensively analyze the influence of characteristics on surrounding rock energy field, stress field, and displacement field under different lateral pressure in a deep roadway. The fundamental grid modeling was done with the three-dimensional modeling software Rhino, which was subsequently translated to the particle flow discrete element software PFC3Dfor numerical simulation. Under the impact of various lateral pressure coefficients, the evolution laws of the energy field, stress field, and displacement field of surrounding rock in disturbed areas were thoroughly investigated. The results demonstrate that:(1) The internal stress field is altered due to different lateral pressure coefficients. The stress field impacts the energy field by changing the particle motion state. The lateral pressure coefficient is positively associated with the kinetic and strain energy in the system. The kinetic energy increases 3.8 times and the strain energy increases 2.6 times when the lateral pressure coefficient increases from 0.6 to 1.5. Under the same lateral horizontal pressure coefficient, the kinetic energy is attenuated to 2%-23% of the initial value, and the strain energy is attenuated to 80%-90% of the initial value once the excavation is done.(2) As the lateral pressure coefficient rises in the excavation phase, the overall stress of the roadway rises. The surrounding rock is categorized into shallow, medium, and deep regions based on the degree of influence of lateral pressure coefficient on the surrounding rock stress field. The change in stress field in the disturbed area of the excavation route demonstrates the phenomenon of deep rock, intermediate rock, and shallow rock. The dominating stress changes in the stress field of surrounding rock as the lateral pressure coefficient increases, reflecting the feature that the variation of arch waist stress is greater than that of arch top and arch bottom, with a maximum absolute variation of 52%.(3) The change in the stress field corresponds to the displacement field. When the lateral pressure coefficient is constant, the displacement value steadily reduces as the distance from the excavation section increases, with a substantial change rate at the shallow region. When the lateral pressure coefficient is varied, the stress field of the surrounding rock in the roadway changes, and the dominant stress changes from vertical stress to horizontal stress. When the lateral pressure coefficient increases, the vertical displacement cloud picture increases progressively. The effect region of excavation disturbance steadily grows in the horizontal range as the prevalent stress in the surrounding rock changes.