开采扰动下断层滑移型岩爆的震源特征及灾变机理

Fault-slip rockbursts can release large amounts of energy and cause huge disasters in deep mining. However, the fundamental research is insufficient for the complex mechanism of disaster formation. The project focuses on the hypocenter characteristics and hazard mechanism for fault-slip rockbursts under mining disturbance, which will be comprehensively investigated by the theoretical analyses, laboratory experiments, numerical simulations, field tests and microseismic monitoring. Firstly，based on boundary constraints for velocity structure of rock mass, hypocenter and origin time of the fault-slip hypocenter, a multi-constraint and self-optimization model for calculating hypocenter locations and origin time will be established. Physical and mechanical parameters of the source waveform and events will be solved on the basis of above results. Secondly, the intrinsic relationship between the far-field dynamic disturbance and hypocenter parameters of fault-slip will be investigated, and numerical simulation models and similar simulation experiments will then be implemented to reproduce dynamic response characteristics under different mining disturbances, and to reveal the causing mechanism of the disaster induced by multi-factors. In addition, based on analysis of evolution rules for the time, space, and scale of hypocenter parameters, dynamic characteristics and failure law will be explored. Finally, dynamic response mechanisms of far-field rock for disturbances of fault-slip hypocenter will be revealed. The mechanism of catastrophe for the system, which is formed by mining disturbances, fault-slip, and response of far-filed rockmass, will be clarified. Therefore, the project will provide theoretical basis for solving complicated warning problems, developing the effective monitoring technology, and improving prevention measures for disasters of fault-slip rockbursts.

深部开采中断层滑移型岩爆会释放大量能量，危害巨大，致灾机理复杂，基础研究薄弱。本项目针对断层滑移型岩爆的震源特征及灾变机理，拟通过理论分析、室内试验、数值仿真、现场试验、微震监测等手段开展研究。首先建立速度结构、震源边界及发震时间的约束条件，构建确定震源位置与发震时间的多约束自优化模型，在此基础上，求解震源波形与事件的物理力学参数，对动力扰动下断层滑移型震源的典型物理力学特征开展系统研究；其次探索远场动力扰动与断层滑移型震源特征参数之间的内在关系，借助数值仿真及室内相似试验再现不同开采扰动下断层的动态响应特性，揭示多因素致灾机理，分析震源的时、空、强演化规律，探索断层滑移的动力学特征；最后揭示断层滑移型震源作用下远场岩体的动态响应机制，阐明“开采扰动-断层滑移-远场响应”系统的灾变机理。本研究可为突破岩爆危险性预警难题、完善断层滑移型岩爆的监测技术、提高灾害防治措施的有效性提供理论依据。

断层滑移型岩爆较应变型岩爆具有震级更大，破坏能力更强的特点，严重制约了硬岩深部资源开采，基础研究薄弱，亟待根本性突破。项目充分运用室内实验、现场试验、数值模拟与理论分析等方法系统开展研究，在震源定位、断层滑移震源机制、灾害防控方面取得的主要创新性成果如下：.1 提出了微震震源定位的解析迭代协同定位方法，不仅利用解析解消除了异常到时的影响，而且基于无需预先测定波速的方法减弱了预先测定波速对定位精度的影响，大幅度提高了断层滑移等震源的定位精度，成果发表在Eng. Fract. Mech.（JCR 1区）。.2 基于全波形分析，揭示了断层滑移的震源机制，探究了岩体对不同震源机制的响应，获得了PGV和PGA的求解方法，为断层滑移区岩体灾害防控提供了数据与技术支撑。成果发表在Int. J. Rock Mech. Min. Sci.（JCR 1区）。.3 反演了复杂矿山环境下的矿岩结构波速场模型，发现采矿开挖严重影响近区岩体结构，高波速场对应着的矿山应力集聚区，低波速场对应着矿岩松动圈，通过波速场反演初步实现了应力积聚区域的辨识与定位，为高应力区能量的调控提供理论依据。.4 求得了断层滑移的震源机制解，颠覆了现有PGV、PGA估计公式中其大小仅与传播距离相关的认识，基于区间分析理论，建立了微震作用下岩体的区间非概率可靠性分析方法，为断层滑移等灾源区域岩体稳定性评估与岩体支护提供依据。.5 提出了断层滑移大震级微震事件的多指标预警方法，综合考虑了b值、H指数和累计贝尼奥夫应变3个指标，大震级微震事件预警准确率达92.59%。该成果应国际声发射学会ISAE的邀请在每两年召开一届的国际声发射大会（WCAE-2017）做主旨报告（Keynote presentation）。.以上成果为深部资源安全高效开采中的断层滑移灾害防控提供科学的理论依据与技术保障。相关成果共发表学术论文23篇，其中SCI检索18篇（第一或通讯作者14篇），3篇为EIS Top 1%高被引论文，EI检索3篇，申请国家发明专利12项，已授权11项，参加国内外学术会议20余次，国际会议主旨报告1次，大会报告十余次。在该项目的资助下，项目负责人董陇军获得2018年国家优秀青年基金项目、2018年湖南省杰出青年基金项目、2016年中国科协青年托举人才项目（中南大学共1项），2017年破格晋升教授。