预制贯通裂缝对砂岩劈裂效果及起裂机制分析  

Analysis of the Splitting Effect and Cracking Mechanism of Prefabricated Through Cracks on Sandstone

作　　者：赖勇[1] 徐国意 张帅 LAI Yong;XU Guoyi;ZHANG Shuai(School of River and Ocean Engineering,Chongqing Jiaotong University,Chongqing 400074;School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074)

机构地区：[1]重庆交通大学河海学院,重庆400074 [2]重庆交通大学土木工程学院,重庆400074

出　　处：《中国煤炭地质》2025年第2期34-40,共7页Coal Geology of China

基　　金：中交路桥科研计划项目(cqjt2023512)。

摘　　要：预制贯通型裂缝用于钻孔劈裂岩石时有重要的辅助作用。首先对不同长度的预制贯通型裂缝岩样展开室内模型试验,再用数值模拟分析其起裂引导机制,得出结论:①预制贯通裂缝用于砂岩劈裂时破岩效果更理想,裂纹曲线更加垂直与光滑,裂缝越长时效果越明显;②预制贯通裂缝长度大于0.5 mm时试件在起裂阶段所需的加载力大幅下降,裂隙发育阶段所需的最大、最小主应力均有明显下降,但裂缝长度越长时下降幅值越小;③预制贯通裂缝让岩样起裂时最小主应力聚于裂缝尖端,裂缝越长,两侧最小主应力分布越对称,最小主应力最大值越小。这些成果有助于深入理解预制贯通型裂缝在钻孔劈裂岩石中的作用,为相关工程实践与理论研究提供有力依据。Prefabricated through cracks play an important auxiliary role in the process of drilling and splitting rocks.Firstly,indoor model tests were carried out on rock samples with prefabricated through cracks of different lengths,and then the crack initiation guiding mechanism was analyzed by means of numerical simulation.The following conclusions were drawn:①When prefabricated through cracks are used for sandstone splitting,the rock-breaking effect is more ideal,and the crack curves are more vertical and smooth.The longer the cracks are,the more obvious the effect is.②When the length of the prefabricated through cracks is greater than 0.5 mm,the loading force required for the specimens in the crack initiation stage decreases significantly,and both the maximum and minimum principal stresses required in the crack development stage decrease obviously.However,the longer the crack length is,the smaller the decreasing amplitude is.③Prefabricated through cracks make the minimum principal stress of rock samples concentrate at the crack tips during the crack initiation stage.The longer the cracks are,the more symmetrical the distribution of the minimum principal stress on both sides is,and the smaller the maximum value of the minimum principal stress is.These results are helpful for indepth understanding of the role of prefabricated through cracks in drilling and splitting rocks,and provide a powerful basis for relevant engineering practice and theoretical research.

关 键 词：贯通型裂缝 劈裂破岩 裂纹诱导 引导机制 室内试验 数值模拟 

分 类 号：TU451.2[建筑科学—岩土工程]