深部巷道破坏分区破裂规律三维相似材料实验

为了探究不同应力状态下巷道围岩的分区破裂规律、影响因素，选择沙土材料为相似材料进行三维模拟实验。试验采用3种加载方式：双向加载、 “圆筒模型加载”和真三轴加载，分别模拟不同采深时围岩的应力状态，巷道的断面形状分别选取了圆形、方形。模型试验研究表明：分区破裂属于空间剪切带破坏，平行于硐室轴线方向应力较大(约是材料抗压强度的1.6倍以上)是形成分区破裂的重要条件。影响分区破裂的因素有围压的大小与分布，开挖巷道所在岩层的相邻岩层性质。围压大且均匀，分区破裂范围大，围压较小且不均匀，分区破裂不明显。层与层之间材料不同时，会影响到裂纹的扩展。而硐室形状对分区破裂的影响因素较小。圆形、方形硐室周围都出现了分区破裂现象。

Three-Dimensional similar material experimental study on zonal disintegration of deep tunnel failure

It is of great importance to conduct deep research into the surrounding rock deformation,the occurrence mechanism of zonal disintegration and its influencing factors.Based on the above factors,the three-dimensional experiments were carried out with the sand as the similar material for exploring the zonal disintegration laws and influencing factors of surrounding rock mass in tunnels.The experiments were carried out under three types of loading conditions,e.g.,biaxial loading,cylindrical passive loading and triaxial loading,to simulate the stress state when the mining depth becomes deeper and deeper.The circular and square were selected respectively as tunnel cross-section.The results show that the zonal disintegration is a kind of space shear zone failure and the stress,parallel to the cavity axis,is larger (far exceeding the material’s compressive strength),which is an important condition for the formation of zonal disintegration.Moreover,the factors that affect the zonal disintegration are mainly related to the size and distribution of rock stress and the adjacent rock formation property during rock excavation.The research indicates that the area of zonal disintegration will be larger,if the rock stress is higher and more homogeneous,otherwise zonal disintegration is not obvious.Furthermore,the property of adjacent rock layers may affect crack propagation.Instead,the shape of cross section has little effect on zonal disintegration as the zonal disintegration occurs around the circular and square tunnel.