深埋洞室超低摩擦型岩爆发生机制与定量预测

发布时间：2018-04-13 05:03

本文选题：岩爆预测 + 超低摩擦　；参考：《重庆大学》2015年硕士论文

【摘要】：深部岩体往往具有非连续性和高地应力的特点,在开挖卸荷作用下通常表现出与浅部岩体截然不同的行为。深部岩体开挖扰动的应力波传播能导致岩体中结构面拉压交替变化,即超低摩擦现象,进而引发岩爆。本文研究了超低摩擦效应的特征,阐述了超低摩擦型岩爆的发生机理,并建立非连续块岩爆预测模型,以工程实例为依托,开展岩爆定量化预测研究相关工作。主要研究工作如下:①通过建立深部岩体的一维非连续块模型,得到任意时刻下块体的位移、速度、加速度以及相邻两块体的相对位移。在此模型基础上探索了岩体中结构面拉压交替变化规律,揭示了深部岩体中超低摩擦效应的存在,分析了其对岩层间破坏和运动的影响。②引入转角自由度,建立深部岩体的二维非连续块模型,通过块体间相互作用力变化规律,得出在瞬时扰动力作用下各块体的平动方程和转动方程。借助显式时域有限差分法,得到块体间相对位移时程曲线,发现了在二维矩形隧洞围岩中存在超低摩擦现象,并提出岩体中结构面拉压交替变化导致破坏从而引发岩爆的超低摩擦型岩爆发生机制。此外,通过参数分析研究了多种地质力学参数对超低摩擦效应的影响。③在深部岩体的二维非连续块模型的基础上建立岩爆预测模型来分析超低摩擦型岩爆的萌生过程和岩爆的烈度特征,并与传统的经验性岩爆烈度分级准则建立了对应关系,验证了岩爆模型对岩爆烈度预测的可行性。通过具体算例,分析地质力学参数如地应力中大小主应力比值、大小主应力大小等对岩爆的发生形式、范围和烈度的影响。④将二维岩爆预测模型应用于锦屏二级水电站施工排水洞工程中,对该工程的不同围岩等级下洞室截面进行岩爆预测分析。通过与现场实测岩爆资料和UDEC模拟结果的对比,表明本文模型与实际工况较吻合,从而验证了本文模型预测岩爆的准确性。
[Abstract]:The deep rock mass is usually discontinuous and high ground stress, and the behavior of the deep rock mass is usually different from that of the shallow rock mass under the action of excavation and unloading.The propagation of stress wave caused by the disturbance of deep rock excavation can lead to the alternation of tension and compression of the structural plane in the rock mass, that is, the phenomenon of ultra-low friction, and then cause the rock burst.In this paper, the characteristics of ultra-low friction effect are studied, the occurrence mechanism of ultra-low friction rockburst is expounded, and the prediction model of discontinuous block rockburst is established. Based on engineering examples, the quantitative prediction of rockburst is carried out.The main work of this paper is as follows: 1. By establishing a one-dimensional discontinuous block model of deep rock mass, the displacement, velocity, acceleration and relative displacement of two adjacent blocks are obtained at any time.On the basis of this model, the alternation law of tension and compression of structural plane in rock mass is explored, the existence of ultra-low friction effect in deep rock mass is revealed, and the influence of this effect on the failure and movement of rock layers is analyzed.The two-dimensional discontinuous block model of deep rock mass is established. The translation equation and rotational equation of each block under instantaneous disturbance force are obtained through the law of interaction between blocks.By means of explicit finite-difference time-domain method, the time-history curves of relative displacement between blocks are obtained, and the phenomenon of ultra-low friction in the surrounding rock of two-dimensional rectangular tunnel is found.The mechanism of ultra-low friction rockburst caused by alternating tension and compression of structural plane in rock mass is put forward.In addition,Based on the two-dimensional discontinuous block model of deep rock mass, the prediction model of rock burst is established to analyze the initiation process of ultra-low friction type rock burst.And the intensity characteristics of rock burst,The corresponding relation is established with the traditional empirical criterion of rock burst intensity classification, which verifies the feasibility of the rock burst model in predicting the rock burst intensity.Through specific examples, the occurrence forms of rockburst caused by geomechanical parameters such as the ratio of major stress in ground stress and the magnitude of principal stress are analyzed.The 2-D rockburst prediction model is applied to the drainage tunnel construction of Jinping II Hydropower Station, and the rock burst prediction analysis is carried out on the section of the cavern under different surrounding rock classes of the project.By comparing with the field measured rock burst data and UDEC simulation results, it is shown that the proposed model is in good agreement with the actual working conditions, thus validating the accuracy of this model in predicting rockburst.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45

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