本文選題：巖石力學(xué) + 大開孔隙率�。� 參考：《昆明理工大學(xué)》2015年碩士論文

【摘要】：巖石是自然界中一種復(fù)雜的天然介質(zhì),由于成巖作用和成巖環(huán)境的差異,其內(nèi)部孕育著大量的節(jié)理、裂紋、微裂隙等缺陷,對(duì)含節(jié)理、裂隙等缺陷巖石力學(xué)特性的研究成為近年來工程界和巖石力學(xué)界所重點(diǎn)關(guān)注的內(nèi)容。通過試驗(yàn)的方法開展對(duì)含裂隙巖石材料力學(xué)特性的研究,對(duì)確保含裂隙巖石工程的穩(wěn)定與安全具有重要的現(xiàn)實(shí)意義。鑒于此,結(jié)合工程應(yīng)用的實(shí)際需要,本文依托國家自然科學(xué)基金項(xiàng)目“頻繁強(qiáng)振和高應(yīng)力環(huán)境下深部節(jié)理化巖巷變形累積轉(zhuǎn)化特征及其失穩(wěn)機(jī)理(項(xiàng)目編號(hào)：41362013)”,為研究原生微裂隙對(duì)白云巖力學(xué)特性的影響規(guī)律和破壞模式,對(duì)含有不同微裂隙的白云巖進(jìn)行單軸壓縮實(shí)驗(yàn)。實(shí)驗(yàn)前,利用聲波法和自然吸水法對(duì)含微裂隙白云巖試件進(jìn)行聲波波速與大開孔隙率的測試,以反映其內(nèi)部隱微裂隙的發(fā)育程度。在此基礎(chǔ)上,對(duì)含原生微裂隙的白云巖進(jìn)行單軸壓縮試驗(yàn),研究含原生微裂隙白云巖的宏觀力學(xué)特性及變形破壞特征,探討白云巖強(qiáng)度、彈性模量、泊松比、聲發(fā)射特征及破壞特性與裂隙發(fā)育程度的關(guān)系,揭示單軸壓縮條件下原生微裂隙對(duì)白云巖力學(xué)特性的影響規(guī)律,獲得的主要結(jié)論如下所述：(1)微裂隙的存在確實(shí)減弱了聲波在巖石介質(zhì)中傳播的速度,隨著巖石試件大開孔隙率的增加,微裂隙對(duì)其縱波波速的減弱作用逐漸減小,即聲波在含裂隙巖石中傳播時(shí)表現(xiàn)出明顯的“裂隙效應(yīng)”。通過擬合發(fā)現(xiàn),白云巖試件的聲波(縱波)波速與其大開孔隙率呈良好的對(duì)數(shù)遞減的關(guān)系。(2)分析統(tǒng)計(jì)到的白云巖試樣圓周表面微裂隙的初始形態(tài)及參數(shù),利用分形幾何學(xué)的研究方法,對(duì)微裂隙的分形維數(shù)進(jìn)行計(jì)算并繪制出分形維數(shù)與微裂隙數(shù)量密度和長度密度的關(guān)系曲線,發(fā)現(xiàn)微裂隙的分形維數(shù)與其數(shù)量密度、長度密度均成線性遞增的變化規(guī)律,說明巖石表面的微裂隙具備良好的分形特征。(3)對(duì)白云巖試樣在單軸壓縮條件下的試驗(yàn)結(jié)果進(jìn)行了分析,通過得到的單軸壓縮下白云巖試樣的應(yīng)力-應(yīng)變曲線,研究了其強(qiáng)度特性、變形特性和聲發(fā)射特性。微裂隙對(duì)白云巖的強(qiáng)度和變形特性產(chǎn)生顯著的影響,白云巖的單軸抗壓強(qiáng)度、彈性模量均表現(xiàn)出隨著大開孔隙率的增大而減小的總體趨勢,且降低幅度呈現(xiàn)出由大逐漸變小的規(guī)律,但從本次試驗(yàn)獲得的數(shù)據(jù)來看,泊松比隨著大開孔隙率的增大沒有表現(xiàn)出明顯的變化規(guī)律。(4)通過對(duì)白云巖試樣最終破壞形態(tài)的分析,從本次試驗(yàn)來看,發(fā)現(xiàn)含天然微裂隙白云巖試件在單軸壓縮作用下存在張拉破壞、拉剪復(fù)合破壞和沿裂隙弱面剪切破壞三種類型的宏觀破裂面,經(jīng)分析后發(fā)現(xiàn),原始微裂隙的分布狀態(tài)對(duì)單軸壓縮條件下白云巖試樣的具體破壞模式有較大的影響。(5)對(duì)單軸壓縮條件下白云巖的微裂隙損傷演化過程進(jìn)行了整體分析,得出試樣在受壓過程中裂紋的起裂順序、擴(kuò)展、和貫通等情況會(huì)因初始微裂隙的幾何分布的不同有較大的差異。
[Abstract]:Rock is a complex natural medium in nature. Due to the difference between diagenesis and diagenetic environment, the rock has a large number of defects, such as joints, cracks, micro cracks and so on. The research on the mechanical properties of defects, such as joints and cracks, has become a major concern in the field of engineering and rock rock force in recent years. The study of the mechanical properties of fractured rock materials is of great practical significance for ensuring the stability and safety of fractured rock engineering. In view of the actual needs of the engineering application, this paper relies on the National Natural Science Foundation Project "the deformation accumulation and transformation characteristics of the deep jointed rock roadway under the frequent strong vibration and high stress environment." The mechanism of instability (item number: 41362013) ", in order to study the influence law and failure mode of the primary microcracks on the mechanical properties of dolomite, the uniaxial compression test of dolomite with different micro cracks was carried out. Before experiments, the acoustic wave velocity and the large open porosity were tested by sound wave method and natural water absorption method. In order to reflect the development degree of the internal microfracture, the uniaxial compression test of dolomite containing primary microfracture was carried out on this basis, and the macroscopic mechanical properties and deformation and failure characteristics of the dolomite containing primary microfracture were studied, and the intensity, modulus of elasticity, Poisson's ratio, acoustic emission and fracture development of dolomite were discussed. The main conclusions obtained are as follows: (1) the existence of micro fissure does weaken the velocity of sound wave propagation in the rock medium. With the increase of the porosity of the rock specimen, the weakening effect of the micro fissure on its longitudinal wave velocity decreases gradually. Sound waves show a clear "fissure effect" in the propagation of fractured rocks. Through fitting, it is found that the acoustic (P-wave) wave velocity of the dolomite specimen has a good logarithmic decrease in the large open porosity. (2) the analysis of the initial morphology and parameters of the circumferential surface microcracks of the dolomite specimen and the study of the fractal geometry The fractal dimension of the micro fissure is calculated and the relation curve of the number density and the length density of the micro fissure is drawn. It is found that the fractal dimension of the micro fissure is linearly increasing with the number density and the length density, which shows that the micro fissure of the rock surface has good fractal characteristics. (3) the dolomite sample The experimental results under uniaxial compression are analyzed. The strength and deformation characteristics and acoustic emission characteristics of the dolomite are studied by the stress-strain curves of the dolomite samples under uniaxial compression. The micro fissure has a significant influence on the strength and deformation characteristics of dolomite. The uniaxial compressive strength and modulus of elasticity of dolomite are all manifested. The general tendency to decrease with the increase of the porosity of large open porosity and the decreasing amplitude shows the law of gradually decreasing, but from the data obtained in this experiment, the Poisson's ratio does not show obvious change law with the increase of the large open porosity. (4) through the analysis of the final destruction form of the dolomite specimen, this test comes from this test. It is found that there are three types of macroscopic fracture surface, including tensile failure, tensile shear composite failure and shear failure along fissures, and it is found that the distribution state of the original microfracture has a great influence on the concrete failure mode of the dolomite specimen under uniaxial compression. (5) The evolution process of the micro fracture damage of dolomite under uniaxial compression is analyzed. It is concluded that the crack initiation sequence, expansion and penetration of the specimen in the compression process are different because of the difference in the geometric distribution of the initial microcracks.
【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU452

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 李樹忱;汪雷;李術(shù)才;韓建新;;不同傾角貫穿節(jié)理類巖石試件峰后變形破壞試驗(yàn)研究[J];巖石力學(xué)與工程學(xué)報(bào);2013年S2期

，

本文編號(hào)：1914685