本文選題：類巖石材料　切入點：裂紋張開度　出處：《重慶大學》2014年碩士論文　論文類型：學位論文

【摘要】：由于構(gòu)造應力場的長期作用，巖石不是均質(zhì)的，而是由許多節(jié)理、裂紋、斷層、滑動面等構(gòu)成的非均質(zhì)各向異性結(jié)構(gòu)體。根據(jù)國內(nèi)外的研究并結(jié)合工程實踐可知，含裂紋巖體的失穩(wěn)和破壞都是通過巖體內(nèi)部裂紋的張開、擴展而產(chǎn)生的貫通滑移面所引起的。因此通過在類巖石材料試樣中預制原始裂紋進行相似模型試驗研究有重要的工程指導意義。很多學者對含兩根不同空間分布裂紋試樣的研究做了很多工作，但并未考慮裂紋張開度對裂紋起裂、擴展、貫通以及巖體破壞的影響。本文為了探究裂紋張開度對裂紋起裂應力、起裂模式、擴展路徑、貫通模式以及巖體強度和應力應變的影響，主要做了以下工作并取得了相應成果： ①結(jié)合實驗目的及實驗條件，進行了實驗方案的設計。確定試樣尺寸并制作模具，設置了三種原始裂紋張開度，分別為0.5mm、1mm、2mm，，同時設置五種不同的裂紋空間分布。利用HG100K高速動態(tài)分析系統(tǒng)對試樣加載過程進行圖像采集，并記錄了裂紋起裂、擴展、貫通的整個過程。利用CMT5504電子萬能試驗機對試樣進行單軸壓縮，通過微機系統(tǒng)獲得了相應的試驗數(shù)據(jù)。 ②新生裂紋類型主要有翼形裂紋、次生共面裂紋和次生傾斜裂紋三種。裂紋張開度對裂紋起裂模式的影響表現(xiàn)為：隨著裂紋張開度的增大，其新生裂紋類型增多，新生裂紋的數(shù)量也隨之增加。裂紋張開度不變時，裂紋傾角對裂紋起裂模式的影響表現(xiàn)為：隨著裂紋傾角的增大，其新生裂紋類型增多。 ③裂紋張開度對裂紋貫通模式的影響主要有三種情況：隨著裂紋張開度的增大，1）試樣的破壞逐漸由單純的剪切破壞轉(zhuǎn)變?yōu)橛蓮埨茐拿婧图羟衅茐拿尕炌ㄋ碌钠茐模?）試樣的破壞逐漸由翼形裂紋和次生傾斜裂紋貫通破壞轉(zhuǎn)變?yōu)橐硇瘟鸭y和次生共面裂紋貫通破壞；3）而在翼形裂紋相互搭接貫通的張拉破壞模式下，裂紋張開度對其幾乎沒有影響。裂紋張開度相同時，裂紋傾角對裂紋貫通模式的影響表現(xiàn)為：試樣的破壞逐漸由翼形裂紋和次生傾斜裂紋貫通破壞轉(zhuǎn)變?yōu)榧羟衅茐摹?④裂紋張開度對試樣力學特性有較明顯影響，即隨著張開度的增加：試樣的峰值強度逐漸減��；試樣的起裂應力逐漸增大，試樣在峰值強度后更容易起裂；試樣的極限應變逐漸減小。同時，裂紋張開度越大，試樣應力-應變曲線中，峰值強度后試樣的應力減小得越快，殘余變形量也越小。
[Abstract]:Because of the long-term action of the tectonic stress field, the rock is not homogeneous, but is composed of many joints, cracks, faults, sliding surfaces and other heterogeneous anisotropic structures. The instability and failure of cracked rock mass are through the opening of cracks inside the rock mass. Therefore, it is of great significance to study the similar model test of prefabricated original cracks in rock-like material samples. Many scholars have studied two different spatial distributions. A lot of work has been done in the study of cracked specimens. However, the effect of crack opening on crack initiation, propagation, penetration and rock mass failure is not considered. Through the model and the impact of rock mass strength and stress and strain, the main work has done the following and achieved the corresponding results:. 1. According to the experimental purpose and experimental conditions, the experimental scheme is designed. The sample size is determined and the mould is made, and three kinds of original crack opening degree are set up. At the same time, five different kinds of crack spatial distribution are set up. The images of the specimen loading process are collected by HG100K high-speed dynamic analysis system, and the crack initiation and propagation are recorded. Uniaxial compression of the sample was carried out by using CMT5504 electronic universal testing machine, and the corresponding test data were obtained by microcomputer system. (2) the main types of new crack are wing crack, secondary coplanar crack and secondary inclined crack. The effect of crack opening on crack initiation mode is as follows: with the increase of crack opening, the new crack type increases. When the crack opening degree is constant, the effect of crack inclination on crack initiation mode is as follows: with the increase of crack inclination, the type of new crack increases. (3) the influence of crack opening degree on crack through-through mode is mainly threefold: with the increase of crack opening degree, the failure of specimen gradually changes from simple shear failure to tensile failure plane and shear failure surface transfixion. The failure of the specimen is gradually changed from the wing crack and the secondary inclined crack to the wing crack and the secondary coplanar crack. When the crack opening degree is the same, the effect of crack inclination angle on crack through-through mode is shown as follows: the failure of specimen is changed from wing crack and secondary inclined crack through failure to shear failure. (4) the crack opening degree has obvious influence on the mechanical properties of the specimen, that is, with the increase of the opening degree, the peak strength of the specimen decreases gradually, the initiation stress of the specimen increases gradually, and the specimen starts to crack more easily after the peak strength. At the same time, the larger the crack opening degree is, the faster the stress decreases after the peak strength and the smaller the residual deformation in the stress-strain curve.
【學位授予單位】：重慶大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU45

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