不同类型岩爆孕育过程中震源体积自相似分布的分形特征分析
Analysis for Self-similarity and Fractal Characteristic of Micro-seismic Volume During the Evolution of Different Types of Rock-burst
作者：于洋(华东交通大学 岩土工程基础设施安全与控制重点实验室, 江西 南昌 330013)；晏志禹(华东交通大学 岩土工程基础设施安全与控制重点实验室, 江西 南昌 330013)；徐长节(华东交通大学 岩土工程基础设施安全与控制重点实验室, 江西 南昌 330013)；刘金泉(华东交通大学 岩土工程基础设施安全与控制重点实验室, 江西 南昌 330013)；耿大新(华东交通大学 岩土工程基础设施安全与控制重点实验室, 江西 南昌 330013)
Author：YU Yang(Key Lab. of Geotechnical Eng. Infrastructure and Safety Control, East China Jiaotong Univ., Nanchang 330013, China)；YAN Zhiyu(Key Lab. of Geotechnical Eng. Infrastructure and Safety Control, East China Jiaotong Univ., Nanchang 330013, China)；XU Changjie(Key Lab. of Geotechnical Eng. Infrastructure and Safety Control, East China Jiaotong Univ., Nanchang 330013, China)；LIU Jinquan(Key Lab. of Geotechnical Eng. Infrastructure and Safety Control, East China Jiaotong Univ., Nanchang 330013, China)；GENG Daxin(Key Lab. of Geotechnical Eng. Infrastructure and Safety Control, East China Jiaotong Univ., Nanchang 330013, China)
收稿日期：2017-09-29 年卷（期）页码：2019,51(1):121-128
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：微震;自相似;分形;应变–结构面滑移型岩爆;应变型岩爆
Key words：micro-seismic;self-similarity;fractal;strain-structure slip rock-burst;strain rock-burst
基金项目：国家自然科学基金资助项目（51509092）；江西省科技厅重点研发资助项目（20181BBG70052）；江西省交通厅科研项目资助（2017D0036）
中文摘要
岩爆严重威胁着深部岩体隧洞的施工安全，并造成大量的人员伤亡及财产损失。在深部岩体隧洞岩爆灾害的孕育及发生过程经常伴随一系列的微震事件；通过针对微震事件发生的时间、空间位置、数量多少、能量大小及震源体积分布等特征参数进行分析，有助于认识岩体的破裂机制，进而为岩爆等动力地质灾害的研究与防治提供理论基础。采用理论分析与微震监测相结合的研究手段，基于锦屏Ⅱ级水电站深埋引水隧洞施工过程中大量不同类型（即时性应变–结构面滑移型岩爆、即时性应变型岩爆）、不同等级即时性岩爆的典型案例，针对岩爆孕育及发生的动态过程展开震源体积分布的自相似特征及分形行为研究。结果表明：深部岩体隧洞开挖即时性岩爆孕育过程中的微震源体积分布表现出良好的自相似性，其自相似系数均大于0.97；对于不同类型的即时性岩爆，其微震信息震源体积分形维数均随着岩爆孕育过程不断增加，岩爆发生时达到最大值的特征；应变–结构面滑移型岩爆过程中每天的震源体积分形维数分布在0.1～0.8范围内，应变型岩爆过程中每天的震源体积分形维数分布在0.4～1.3范围内，岩爆发生当天的分形维数均大于1.0。研究成果对高地应力条件下岩爆灾害动态预警体系的建立具有重要的指导意义，同时可为中国深部岩体隧洞开挖过程的安全设计提供必要的科学依据和支撑。
英文摘要
Rock-burst is a serious threat to the construction safety of deep tunnels, which causes huge economic loss and staff casualties. The evolution process of rock-bursts is accompanied by a series of micro-seismic events. Analyzing and processing these characteristic parameters about the microfracturing such as size, time, space, energy, volume, etc, which is helpful to understand the fracture mechanism of rock mass, and provides a theoretical basis for the study of rock-burst disaster. In this research, theoretical analysis combined with micro-seismic monitoring were used. Based on the hundreds of immediate rock-bursts (including immediate strain structure slip rock-bursts and immediate strain rock-bursts), with different types and intensities, occurred in four deep headrace tunnels at Jinping-Ⅱ hydropower station in Sichuan province, China. The self-similarity characteristic and fractal behavior of micro-seismic volume distributions during the dynamic evolution process of such rock-bursts were studied. The achieved results are as follows:The volume distribution of micro-seismic events during the development of immediate rock-bursts shows great self-similarity, the value of correlation coefficient are all greater than 0.97. For different types of immediate rock-bursts, the daily volume fractal dimension increases during the evolution of immediate rock-bursts, and they totally increase up to a certain threshold value before the rock-burst occur. The volume fractal dimension values on each day were between 0.8 and 0.1 for the evolution of immediate strain structure slip rock-bursts, but those of immediate strain rock-bursts were between 0.4 and 1.3, and both of them are greater than 1.0 when the rock bursts. The micro-seismic energy fractal dimension can be used as a significant guideline to build up a warning system and reduce the risk of rock-bursts during construction under high in-situ stress condition.
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