本文關(guān)鍵詞：真三軸卸載下深部巖體破裂特性及誘發(fā)型巖爆機(jī)理研究　出處：《中南大學(xué)》2013年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 深部巖體 真三軸 卸載 板裂破壞 動(dòng)靜組合 巖爆

【摘要】：礦山深井開采面臨著眾多難題,如何改善深部巖體所處的復(fù)雜力學(xué)環(huán)境——高地應(yīng)力、高地溫、高巖溶水壓力及爆破、機(jī)械開挖等引起的動(dòng)力擾動(dòng)(“三高一擾動(dòng)”)就是其中之一。高應(yīng)力意味著高巖體儲(chǔ)能。在工程開挖卸荷過程中,高應(yīng)力巖體內(nèi)的高儲(chǔ)能被誘發(fā)釋放,從而導(dǎo)致圍巖破裂并誘發(fā)巖爆等大規(guī)模工程災(zāi)害。本文從高地應(yīng)力受力環(huán)境出發(fā),利用自行研制的巖石真三軸電液伺服誘變(擾動(dòng))試驗(yàn)系統(tǒng),深入研究真三軸卸荷狀態(tài)下高應(yīng)力巖石的力學(xué)特性及動(dòng)載荷誘發(fā)巖爆的可能性,揭示深部巖爆災(zāi)害的擾動(dòng)誘發(fā)機(jī)理。主要研究內(nèi)容及研究成果如下： (1)深部工程巖體主要受到卸荷損傷和應(yīng)力調(diào)整集中的作用,利用自行設(shè)計(jì)的巖石真三軸電液伺服誘變(擾動(dòng))試驗(yàn)系統(tǒng)對(duì)不同應(yīng)力狀態(tài)下花崗巖、紅砂巖及水泥砂漿的立方試件進(jìn)行了真三軸卸載壓縮破壞試驗(yàn)。研究結(jié)果表明卸載后二維受力下巖石的抗壓強(qiáng)度隨中間主應(yīng)力的增大而增大,但增大的幅度逐漸降低。當(dāng)單軸壓縮或中間主應(yīng)力較小時(shí),巖石破壞模式為剪切破壞；隨著中間主應(yīng)力的增大,巖石的破壞模式逐漸由剪切破壞轉(zhuǎn)變?yōu)榘辶哑茐摹?從本文的研究結(jié)果得出巖石發(fā)生板裂破壞不僅與巖性有關(guān),還與其應(yīng)力狀態(tài)有關(guān)。 (2)基于莫爾-庫倫強(qiáng)度準(zhǔn)則分析了巖石破壞模式的轉(zhuǎn)變。通過莫爾-庫倫定律計(jì)算的不同應(yīng)力水平下巖石的計(jì)算強(qiáng)度與花崗巖和紅砂巖試件的測(cè)試強(qiáng)度的比較發(fā)現(xiàn),測(cè)試強(qiáng)度值明顯低于計(jì)算強(qiáng)度值,說明巖石破壞時(shí)強(qiáng)度不再符合莫爾-庫倫強(qiáng)度準(zhǔn)則,破壞模式由剪切破壞轉(zhuǎn)變?yōu)榘辶哑茐摹?(3)利用聲發(fā)射測(cè)試系統(tǒng)與紅外熱像儀對(duì)巖石板裂破壞時(shí)的聲發(fā)射數(shù)及溫度變化進(jìn)行了監(jiān)測(cè)。通過聲發(fā)射計(jì)數(shù)分析得出剪切裂紋的產(chǎn)生伴隨著整個(gè)加載過程,而板裂裂紋不同于剪切裂紋,是在巖石受力達(dá)到一定程度時(shí)才產(chǎn)生。 單軸壓縮條件下,巖石發(fā)生剪切破壞,壓縮椎體表面溫度變化顯著；當(dāng)中間主應(yīng)力較小時(shí),巖石下半部分先發(fā)生破壞,然后再發(fā)生整體破壞,巖石破壞形式為剪切破壞；當(dāng)中間主應(yīng)力較大時(shí),整個(gè)試樣表面溫度均有明顯的升高,說明巖石的破壞形式為板裂破壞。 (4)根據(jù)地下工程開挖下巖體受力路徑及板裂破壞發(fā)生條件,開展了擾動(dòng)誘發(fā)巖爆試驗(yàn)。對(duì)真三軸卸載下試件施加擾動(dòng)載荷,研究證明無論擾動(dòng)載荷是垂直最大主應(yīng)力方向還是沿著最大主應(yīng)力方向施加,只要載荷幅值達(dá)到一定程度均可誘發(fā)巖爆破壞。根據(jù)擾動(dòng)誘發(fā)巖爆試驗(yàn),提出了擾動(dòng)誘發(fā)巖爆結(jié)構(gòu)演化模型。 (5)運(yùn)用離散元PFC3D程序?qū)_動(dòng)誘發(fā)巖爆進(jìn)行了數(shù)值模擬,從微觀角度分析得到了與試驗(yàn)結(jié)果相一致的結(jié)論。當(dāng)擾動(dòng)載荷的幅值為300、400、500kN時(shí),試件內(nèi)部有微裂紋擴(kuò)展,但趨于穩(wěn)定,巖石未發(fā)生破壞；但擾動(dòng)載荷幅值為600kN時(shí),微裂紋擴(kuò)展迅速,巖石發(fā)生巖爆破壞。
[Abstract]:Deep mine mining is faced with many difficulties, how to improve the complex mechanical environment of deep rock mass-high ground stress, high ground temperature, high karst water pressure and blasting. The dynamic disturbance caused by mechanical excavation ("three high and one disturbance") is one of them. High stress means high rock mass energy storage. In this paper, based on the stress environment of high ground stress, the real triaxial electro-hydraulic servo mutagenic (disturbance) test system of rock is developed. The mechanical properties of high stress rock under true triaxial unloading state and the possibility of rock burst induced by dynamic load are studied in depth, and the disturbance inducing mechanism of deep rock burst disaster is revealed. The main research contents and results are as follows: 1) the deep engineering rock mass is mainly affected by unloading damage and stress adjustment concentration. The granite under different stress states is treated by using the self-designed true triaxial electro-hydraulic servo mutagenic (disturbance) test system. The true triaxial unloading compression failure test was carried out on the cubic specimen of red sandstone and cement mortar. The results show that the compressive strength of rock increases with the increase of intermediate principal stress after unloading. When uniaxial compression or intermediate principal stress is small, the failure mode of rock is shear failure. With the increase of intermediate principal stress, the failure mode of rock changes from shear failure to plate fracture. From the results of this paper, it is concluded that the failure of rock slabs is not only related to lithology, but also to its stress state. 2). Based on Mohr Coulomb strength criterion, the transformation of rock failure mode is analyzed. The comparison of calculated rock strength with that of granite and red sandstone specimens under different stress levels calculated by Mohr Coulomb's law is made. . The measured strength value is obviously lower than the calculated strength value, which indicates that the strength of rock is no longer in accordance with the Mohr Coulomb strength criterion, and the failure mode is changed from shear failure to plate crack failure. 3). Acoustic emission measurement system and infrared thermal imaging system are used to monitor the number of acoustic emission and the temperature change of rock slab cracking. By acoustic emission counting analysis, it is concluded that the shear crack is accompanied by the whole loading process. The crack of plate is different from the shear crack, and it only occurs when the stress of rock reaches a certain degree. Under uniaxial compression, shear failure occurs in rocks, and the surface temperature of compression vertebrae changes significantly. When the intermediate principal stress is small, the failure of the lower part of the rock occurs first, then the whole failure occurs, and the failure of the rock is in the form of shear failure. When the intermediate principal stress is larger, the surface temperature of the whole specimen increases obviously, which indicates that the failure form of rock is plate fracture. 4) according to the stress path of rock mass under excavation of underground engineering and the occurrence condition of slab crack failure, the disturbance induced rockburst test is carried out. The disturbance load is applied to the specimen under true triaxial unloading. It is proved that no matter whether the disturbance load is applied in the vertical direction of the maximum principal stress or along the direction of the maximum principal stress, the rockburst damage can be induced as long as the amplitude of the load reaches a certain degree. A model for the evolution of rock burst structure induced by disturbance is proposed. 5) numerical simulation of disturbance induced rockburst is carried out by using discrete element PFC3D program, and the results are in agreement with the experimental results from the microscopic point of view. When the amplitude of disturbance load is 300,400. At 500kN, there is a microcrack propagation inside the specimen, but it tends to be stable and the rock is not destroyed. However, when the amplitude of disturbance load is 600 KN, the microcrack grows rapidly and rock burst occurs.
【學(xué)位授予單位】：中南大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2013
【分類號(hào)】：TU45

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