深部巷道围岩塑性区岩体非连续变形及其控制

The deformation and failure of surrounding rock in the deep roadway is the result of the malignant expansion of the plastic zone into the interior of the surrounding rock, which is derived from the discontinuous deformation caused by the effect of shear dilation between the cracked blocks in the creep phase of the post-peak phase. On the basis of fully understanding the stress environment and mechanical characteristics of the surrounding rock in the deep roadway, taking the occurrence and development of discontinuous deformation of rock mass in the plastic zone as the main line, the development process of the rock mass from continuous deformation to discontinuous deformation and post-peak creep characteristics of rock mass under various stress environments will be studied. The purpose is to discover the temporal and spatial evolution of the discontinuous deformation in the plastic zone of the deep roadway, reveal the nature and control degree of discontinuous deformation caused by creep of surrounding rock, get the cause and component of the "given deformation" of surrounding rock, explain the mechanical nature of "given deformation", and finally put forward the principle of stability control of surrounding rock of deep roadway based on preventing the excessive discontinuous deformation of the surrounding rock. New control method for surrounding rock of deep roadway with new supporting materials such as synergistic support structure of cable-U type steel and elastic cable will be used for field application research to further improve and enrich the stability control theory and practical countermeasures for the surrounding rock of large deformation roadway.

深部巷道围岩变形与破坏是塑性区向围岩内部恶性扩展的结果，塑性区恶性扩展则源于塑性区岩体峰后蠕变过程中破裂块体间剪胀作用而引起的非连续变形。本项目在充分认识深部巷道围岩应力环境、力学特性的基础上，针对深部大变形巷道塑性区围岩非连续变形及其控制问题，以围岩塑性区岩体非连续变形的发生与发展为主线研究塑性区岩体由连续变形到非连续变形的发展过程，各种应力环境下深部岩体峰后蠕变特性，发现深部巷道塑性区非连续变形的时空演化规律，揭示深部巷道围岩因蠕变引起的非连续变形本质特征及可控制程度，得到深部巷道围岩“给定变形”成因及形变构成，阐释“给定变形”的力学本质，提出基于防止塑性区围岩产生过量非连续变形的深部巷道围岩稳定性控制原理。以具有自主知识产权的锚索-U型钢协同支护结构和弹性锚索等新支护材料为主的深部巷道围岩控制新方法进行现场应用研究，进一步完善和丰富深部大变形巷道围岩稳定性控制理论和实用对策。

本项目以深部大变形巷道为工程背景，通过理论分析、实验室试验、数值模拟计算、现场工程应用等手段，研究了大变形巷道塑性区围岩非连续变形及其控制问题，以塑性区岩体非连续变形的发生与发展为主线，研究塑性区岩体由连续变形到非连续变形的发展过程，研究了锚杆支护与围岩变形的作用关系，揭示了深部巷道围岩“给定变形”的力学机制；推导了支护作用下巷道塑性区的边界方程，揭示了塑性区不规则形态形成的力学机制；研究了锚杆对围岩非连续变形的控制作用。最后提出了深部巷道塑性区围岩非连续变形的稳定控制技术，取得了以下创新性成果或发现：巷道埋深越大，围岩的“给定变形”也越大，锚杆支护对于控制巷道围岩变形是科学有效的，但在现有的支护技术水平下，锚杆支护无法保证巷道围岩不发生变形；由于锚杆和围岩体在材料上的差异，在实际工程中，锚杆对于围岩的作用具有明显的滞后性，表现为围岩体已经破坏锚杆才刚刚开始发挥作用；锚杆支护的主要作用是控制围岩塑性区内非连续性、非协调性扩容变形，而对于围岩连续性变形的控制作用十分微弱；科学合理的支护设计应当根据围岩各位置塑性区深度进行协调支护、区别支护设计，使得各位置锚杆锚固基础均位于弹性岩体，避免局部强支护造成过度支护以及局部弱支护造成支护失效。基于以上研究成果，提出了深部巷道塑性区围岩非连续变形的稳定控制技术，并在平煤、云南湾田等矿区进行应用，按照新的技术方案，塑性区围岩非连续性变形得到有效控制，巷道维护效果显著改善，取得了明显的社会经济效益，推动了巷道支护理论与技术的发展。