爆炸荷载作用下深部岩体分区破裂模型试验研究
发布时间：2018-09-07 21:23
【摘要】：随着地下工程开采深度的不断增加,在高地应力、高地温、高渗透压和爆破开挖扰动等特殊工程环境下,深部地下工程岩体产生了诸如分区破裂现象、围岩大变形、岩爆等新的工程地质灾害现象。针对高轴地应力深部岩体分区破裂现象,采用理论分析、三维相似物理模型试验、颗粒流数值模拟和现场监测相结合的方法,研究了爆炸荷载对高轴地应力条件下深部岩体分区破裂的影响机理与深部围岩的变形破坏规律。基于Hoek-Brown准则,理论分析了深部圆形洞室在高轴地应力和静水压力条件下围岩的弹性应力场,推导了洞周围岩爆破损伤效应的破裂区分布区域,得出爆炸荷载对深部围岩破裂区宽度的影响范围。采用“先加载、后开洞、再超载”的试验方法,开展了人工凿挖、预埋件抽出和爆破开挖3种开挖方式的深部岩体分区破裂三维相似物理模型试验。试验表明,模型洞室开挖完毕,3种开挖方式的模型洞周应力和应变随距洞壁距离的增加均呈现出波峰与波谷间隔分布的非线性变化,验证了分区破裂是高轴地应力条件下的一种特殊破坏模式。轴向超载过程中,洞周围岩开始出现环状破裂,在环状破裂区内应变迅速增大,在环状破裂区附近应变迅速减小。超载完毕,洞周应变呈现出波峰与波谷的间隔分布,分别对应于围岩破裂区与非破裂区；洞周径向应力也表现出相似的变化趋势。模型洞室拱顶和帮部荷载的增加会限制模型洞周的破裂区范围。爆炸荷载在洞壁附近围岩体内产生大量的微裂纹,造成围岩体力学性能的劣化和完整性降低；在高轴地应力条件下,微裂纹扩展、贯通,形成宏观破裂区,使洞壁围岩体的破坏加剧,围岩破裂区的范围扩大；后一层破裂区半径约为前一层破裂区半径的1.28倍。建立了深部岩体爆破开挖三维颗粒计算模型,对节理倾角不同的深部岩体进行数值分析,揭示了爆炸荷载作用时间和层状节理面倾角对深部地下工程岩体分区破裂的影响。随着层状节理面倾角的增大,爆破开挖完毕颗粒模型洞周围岩破裂区范围、张拉和剪切裂纹数与应变能增量均呈现出先增大后减小的变化趋势；当层状节理倾角为600时,围岩体破裂区范围最大。开展了锚固支护深部岩体在高轴地应力状态下爆破开挖相似模型试验,发现锚杆和锚索联合支护部位未出现分区破裂,而未支护部位出现了分区破裂,分析得出锚杆和锚索的联合作用可实现围岩应力的转移和重分布,揭示了锚固支护对深部岩体分区破裂的抑制机理。现场爆破损伤监测表明,采用钻爆法施工的巷道,左帮爆破损伤区在6m范围内,右帮爆破损伤区在7m范围内,且3m范围内围岩体的损伤程度较大。
[Abstract]:With the increasing mining depth of underground engineering, in the special engineering environment such as high ground stress, high ground temperature, high permeability pressure and disturbance of blasting excavation, the deep underground engineering rock mass has produced such phenomena as zonal fracture and large deformation of surrounding rock. Rock burst and other new engineering geological disasters. In view of the phenomenon of zone fracture of deep rock mass with high axial geostress, the method of combining theoretical analysis, three-dimensional physical model test, numerical simulation of particle flow and field monitoring is used. The influence mechanism of explosive load on the zonal fracture of deep rock mass under high axial stress and the deformation and failure law of deep rock mass are studied. Based on Hoek-Brown criterion, the elastic stress field of surrounding rock in deep circular cavern under high axial geostress and hydrostatic pressure is theoretically analyzed. The influence range of explosion load on the width of fracture zone of deep surrounding rock is obtained. By using the test method of "loading first, then opening holes and then overloading", the three-dimensional similar physical model tests of deep rock mass subzone fracture are carried out, which are excavated by artificial chisel, pre-buried parts extraction and blasting excavation. The experimental results show that the stress and strain around the tunnel show nonlinear variation of the interval between the wave peak and the trough with the increase of the distance from the wall of the tunnel. It is verified that zonal fracture is a special failure mode under high axial stress. In the process of axial overloading, the surrounding rock begins to appear annular fracture, the strain increases rapidly in the annular fracture zone, and the strain decreases rapidly near the annular fracture zone. At the end of the overload, the strain around the hole shows the interval distribution between the wave peak and the trough, corresponding to the fracture zone of surrounding rock and the non-fracture zone respectively, and the radial stress around the hole also shows a similar change trend. The increase of the arch roof and the roof load of the model chamber will limit the range of the rupture zone around the model hole. The explosion load produces a large number of microcracks in the surrounding rock near the wall of the tunnel, which results in the deterioration and integrality of the mechanical properties of the surrounding rock, and under the condition of high axial in-situ stress, the microcracks propagate and pass through, forming a macroscopic fracture zone. The destruction of wall rock body is aggravated and the range of surrounding rock fracture zone is enlarged, and the radius of the latter layer is about 1.28 times of that of the former one. A three-dimensional particle calculation model for blasting excavation of deep rock mass is established. The numerical analysis of deep rock mass with different joint inclination is carried out, and the effects of time of explosion load and dip angle of layered joint plane on the zonal fracture of rock mass in deep underground engineering are revealed. With the increase of the inclined angle of the layered joint surface, the range of rock fracture area around the granular model hole after blasting excavation, the number of tensile and shear cracks and the strain energy increment show a trend of first increasing and then decreasing, when the dip angle of the layered joint is 600, The fracture zone of surrounding rock is the largest. The similar model test of blasting excavation of deep rock mass with anchor support under high axial in-situ stress is carried out. It is found that there is no zonal rupture in the joint support part of anchor rod and anchor cable, but there is a partition fracture in the unsupported part. It is concluded that the combined action of anchor rod and anchor cable can realize the stress transfer and redistribution of surrounding rock mass, and the mechanism of anchoring support to the zonal fracture of deep rock mass is revealed. Field blasting damage monitoring shows that the damage zone of the left side blasting is within 6 m, the right side blasting damage area is within 7 m, and the damage degree of surrounding rock is larger within 3 m.
【学位授予单位】：安徽理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TU45
，
本文编号：2229461
[Abstract]:With the increasing mining depth of underground engineering, in the special engineering environment such as high ground stress, high ground temperature, high permeability pressure and disturbance of blasting excavation, the deep underground engineering rock mass has produced such phenomena as zonal fracture and large deformation of surrounding rock. Rock burst and other new engineering geological disasters. In view of the phenomenon of zone fracture of deep rock mass with high axial geostress, the method of combining theoretical analysis, three-dimensional physical model test, numerical simulation of particle flow and field monitoring is used. The influence mechanism of explosive load on the zonal fracture of deep rock mass under high axial stress and the deformation and failure law of deep rock mass are studied. Based on Hoek-Brown criterion, the elastic stress field of surrounding rock in deep circular cavern under high axial geostress and hydrostatic pressure is theoretically analyzed. The influence range of explosion load on the width of fracture zone of deep surrounding rock is obtained. By using the test method of "loading first, then opening holes and then overloading", the three-dimensional similar physical model tests of deep rock mass subzone fracture are carried out, which are excavated by artificial chisel, pre-buried parts extraction and blasting excavation. The experimental results show that the stress and strain around the tunnel show nonlinear variation of the interval between the wave peak and the trough with the increase of the distance from the wall of the tunnel. It is verified that zonal fracture is a special failure mode under high axial stress. In the process of axial overloading, the surrounding rock begins to appear annular fracture, the strain increases rapidly in the annular fracture zone, and the strain decreases rapidly near the annular fracture zone. At the end of the overload, the strain around the hole shows the interval distribution between the wave peak and the trough, corresponding to the fracture zone of surrounding rock and the non-fracture zone respectively, and the radial stress around the hole also shows a similar change trend. The increase of the arch roof and the roof load of the model chamber will limit the range of the rupture zone around the model hole. The explosion load produces a large number of microcracks in the surrounding rock near the wall of the tunnel, which results in the deterioration and integrality of the mechanical properties of the surrounding rock, and under the condition of high axial in-situ stress, the microcracks propagate and pass through, forming a macroscopic fracture zone. The destruction of wall rock body is aggravated and the range of surrounding rock fracture zone is enlarged, and the radius of the latter layer is about 1.28 times of that of the former one. A three-dimensional particle calculation model for blasting excavation of deep rock mass is established. The numerical analysis of deep rock mass with different joint inclination is carried out, and the effects of time of explosion load and dip angle of layered joint plane on the zonal fracture of rock mass in deep underground engineering are revealed. With the increase of the inclined angle of the layered joint surface, the range of rock fracture area around the granular model hole after blasting excavation, the number of tensile and shear cracks and the strain energy increment show a trend of first increasing and then decreasing, when the dip angle of the layered joint is 600, The fracture zone of surrounding rock is the largest. The similar model test of blasting excavation of deep rock mass with anchor support under high axial in-situ stress is carried out. It is found that there is no zonal rupture in the joint support part of anchor rod and anchor cable, but there is a partition fracture in the unsupported part. It is concluded that the combined action of anchor rod and anchor cable can realize the stress transfer and redistribution of surrounding rock mass, and the mechanism of anchoring support to the zonal fracture of deep rock mass is revealed. Field blasting damage monitoring shows that the damage zone of the left side blasting is within 6 m, the right side blasting damage area is within 7 m, and the damage degree of surrounding rock is larger within 3 m.
【学位授予单位】：安徽理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TU45
，
本文编号：2229461
本文链接：https://www.wllwen.com/kejilunwen/diqiudizhi/2229461.html
