含裂隙类岩石注浆加固后破坏试验研究

来源期刊:中南大学学报(自然科学版)2018年第4期

论文作者:王志 李龙 王朝雅

文章页码:957 - 964

关键词:注浆加固;裂隙;破坏机理;应变分析;类岩石

Key words:grouting reinforcement; crack; failure mechanism; strain analysis; rock-like materials

摘    要:采用白水泥预埋抽条法制作类岩石试样,利用邻苯二甲酸二丁酯增韧的环氧树脂浆液进行注浆,分析加固前后裂尖位置的应变场,揭示加固后多裂隙试样的破坏机理。研究结果表明:加固前后的裂纹萌生位置相同,未注浆试样的起裂角与原裂纹面垂直,注浆后的试样裂缝由起裂位置竖直向上下贯通整个试样,类似于完整试样的单轴压缩破坏,注浆加固能够将裂尖的应力集中有效抑制,同时增强试样的完整性。未注浆的单裂隙试样裂尖最大主应变在达到临界时出现首条裂缝,随后会发生应力重分布,注浆加固后,主应变增长均匀,破坏是由于裂隙充填物与类岩石材料之间的变形不平衡引起的。未注浆的双裂隙试样,裂纹萌生后,韧带区附近最大主应变增加至临界值出现贯通裂缝,断裂类型为I型断裂,注浆加固后双裂隙试样,裂尖附近拉应变几乎同时达到最大值,注浆加固可避免由于不连续节理或裂缝形成应力重分布,使试样形成较为完整的整体,影响注浆效果的主要因素是注浆材料的强度以及其与基体材料的黏结情况。

Abstract: Using white cement as the rock-like materials, the specimens in which the cracks were arranged through pre-installed steel slice were produced. The epoxy resin toughened by dibutyl phthalate (DBP) was used to carry out grouting reinforcement. The failure mechanism of the multi cracks specimens after grouting reinforcement was revealed through strain field analysis of the crack tip. The results show that the crack initiates in the same position for specimen before and after grouting reinforcement. The crack angle of specimens without grouting is perpendicular to the original crack plane and the crack of specimens after grouting is vertically penetrated through the whole specimen from the crack initiation position which is similar to the un-cracked specimen. The grouting reinforcement can effectively restrain the stress concentration of the crack tip and enhance the integrity of the specimen. The first cracks initiate when the maximum principal strain at the crack tip of single crack specimen reaches its critical value and then stress redistribution occurs. After grouting reinforcement, the maximum principal strain increase with a relatively flat trend and the failure occur because of the deformation imbalance between the rock like materials and the fracture fillings. For double cracks specimen without grouting, a penetrating crack occur in the ligament region because the maximum principal strain reaches critical value after the first crack initiates and Mode I fracture occurs. For double cracks specimen after grouting, the tensile strains almost reach their maximum value at the same time. The grouting reinforcement can avoid the formation of stress redistribution and strengthen the integrity of the specimen. The main factors of the grouting effect are the strength of the grouting material and its bonding properties.

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