基于岩饼几何形态测量的原地应力测定方法

岩饼是工程区高地应力的标志之一,其形状与主应力的大小和方向直接相关,岩饼出现时刻通常的应力解除法不能再用于原地应力测量。根据国内外众多学者多年来对岩饼现象的研究成果,提出一种根据岩饼的几何形态测量初步计算三维地应力的方法。经实践验证,与同一工程区其他地应力测量方法的结果相比,岩饼几何形态测量方法确定出三维地应力的方向相差不大,倾角差值在10°以内,方位角之差小于20°,主应力大小满足岩饼出现的条件,具有简便实用的优点。

岩芯饼裂机制及其对工程地质特性影响的分析

提出了岩芯饼裂主要受地应力平均值控制的观点,说明了岩饼表面圆周状对称拉裂坎以及垂直拉裂坎方向擦痕的形成原因,结合工程地质讨论了岩体的弹性模量和内聚力。

河谷应力集中及岩体响应

河谷下切引起的应力集中是显著的 ,河谷地区许多构造形迹及地下工程中出现的若干围岩稳定问题都与此有关。半圆形河谷的应力集中系数为 3 0 7;U字形、V字形河谷的应力集中系数均大于 3。河床岩体处于σ1>σ2 、σ3 ≈ 0的应力状态 ,理论上具有形成分别平行于和与σ1小角度相交的压致拉破坏及两组共轭剪切构造的潜势。河床及部分岸坡岩体中的缓倾角结构面、层间错动带及层间虚脱等宏观构造形迹是这些破坏潜势的具体体现 ;河床岩饼破裂面是上述应力集中引起岩石流变而形成的破劈理。

拉西瓦水电站峡谷地应力场特征研究

本文在分析拉西瓦坝址高地应力现象的基础上,研究了坝轴线剖面地应力的空间变化规律、河谷应力集中程度和范围等,据此进行了河谷应力分带,为恰当选择坝肩嵌入深度和开挖方式提供了科学依据。

Core discing characteristics and mitigation approach by a novel developed drill bit in deep rocks

Core discing often occurs in deep rocks under high-stress conditions and has been identified as an important characteristic for deep rock engineering.This paper presents the formation mechanism of core discing firstly.Then,the interaction between diamond drill bits and rock was analyzed based on numerical modeling.A novel drill bit with an inner conical crown for the mitigation of core discing was designed and verified by simulation experiments.The mitigation method was applied in the cavern B1 of CJPL-Ⅱand satisfactory results had been achieved.The percentage of core discing had been obviously decreased from 67.8%when drilling with a rectangular crown drill bit,to 26.5%when an inner conical crown drill bit had been adopted.This paper gives full insight into core discing characteristics and provides a new method for core discing mitigation;it will potentially contribute to stress measurement in deep rock engineering.