初始應(yīng)力下巖石爆破過程模擬研究
發(fā)布時間：2018-08-07 08:24
【摘要】：由于淺部資源的減少及某些工程的需要,資源開采和隧道開挖都進入了深部地下。深部巖體往往處于高初始地應(yīng)力環(huán)境中,爆破時,巖石在初始應(yīng)力和爆炸載荷的共同作用下而破裂,這個過程非常復(fù)雜,已經(jīng)不能用淺部巖體的爆破理論來分析了。因此有必要對初始應(yīng)力下巖石的爆破過程進行分析。本文利用有限元軟件LS-DYNA和ABAQUS對初始應(yīng)力下的巖石爆破過程進行了數(shù)值模擬研究,完成了如下的工作：(1)從理論上分析了巖石爆破的過程,結(jié)合巖石爆破過程,分析了巖石在爆炸動載荷下的應(yīng)變率效應(yīng)、巖石爆破的動力學進程以及爆炸載荷和初始應(yīng)力的疊加。(2)利用LS-DYNA對初始應(yīng)力下球狀裝藥的巖石爆破過程進行了數(shù)值模擬,對比了不同抵抗線下的爆破漏斗大小,結(jié)果表明：不同抵抗線下形成的爆破漏斗差別很大,本文計算的模型中,抵抗線W=20mm時爆破漏斗最大,初始應(yīng)力不影響球狀裝藥應(yīng)力波的傳播,但會抑制垂直于初始應(yīng)力方向的爆破漏斗的形成；對初始應(yīng)力下柱狀裝藥巖石爆破過程進行了數(shù)值模擬,結(jié)果表明：初始應(yīng)力不影響柱狀裝藥爆炸應(yīng)力波的傳播和衰減,也不影響爆破粉碎區(qū)的形成,但會抑制垂直于初始應(yīng)力方向的裂紋的形成；對卸載初始應(yīng)力下的巖石爆破過程進行了數(shù)值模擬,結(jié)果表明：卸載應(yīng)力波可以改善巖石中應(yīng)力場的分布,并促進爆破裂紋的形成。(3)利用LS-DYNA對初始應(yīng)力下排孔爆破過程和預(yù)裂爆破過程進行了數(shù)值模擬,結(jié)果表明：各炮孔距離合適時,不同炮孔之間形成貫通裂紋,當排孔與初始應(yīng)力平行時,排孔爆破效果最好,排孔與初始應(yīng)力垂直時,排孔爆破效果最差,預(yù)裂爆破中,排狀的預(yù)裂孔、炮孔和初始應(yīng)力平行時,預(yù)裂孔能誘導兩炮孔間裂紋的形成；對初始應(yīng)力下含節(jié)理的巖石爆破過程進行了數(shù)值模擬,結(jié)果表明：節(jié)理對爆炸應(yīng)力波有透射和反射作用,并使巖石產(chǎn)生反射拉伸裂紋,但貫通節(jié)理阻礙了裂紋的進一步擴展,當局部節(jié)理尖端、炮孔連線與局部節(jié)理之間夾角較小時,局部節(jié)理尖端可以誘導裂紋擴展；對初始應(yīng)力下含空區(qū)的巖石爆破過程進行了數(shù)值模擬,結(jié)果表明：空區(qū)給爆破提供了自由面,改善了巖石中應(yīng)力分布和爆破效果。(4)利用ABAQUS對爆生氣體驅(qū)動裂紋擴展過程進行了數(shù)值模擬,結(jié)果表明：隨著裂紋的擴展,爆生氣體壓力減小,裂紋擴展速度降低,當爆生氣體壓力達到臨界壓力時,裂紋停止擴展；對初始應(yīng)力下爆生氣體驅(qū)動裂紋擴展過程進行了數(shù)值模擬,結(jié)果表明：初始應(yīng)力會抑制垂直于初始應(yīng)力方向的裂紋的擴展,當初始裂紋方向與初始應(yīng)力方向或初始應(yīng)力合力方向一致時,裂紋沿著原來的方向擴展,否則,裂紋偏向初始應(yīng)力大的方向擴展。
[Abstract]:Due to the decrease of shallow resources and the need of some projects, resource mining and tunnel excavation have entered deep underground. The deep rock mass is often in the environment of high initial in-situ stress. When blasting, the rock ruptures under the joint action of initial stress and explosion load. This process is very complicated and can not be analyzed by the blasting theory of shallow rock mass. Therefore, it is necessary to analyze the rock blasting process under initial stress. In this paper, the numerical simulation of rock blasting process under initial stress has been carried out by using finite element software LS-DYNA and ABAQUS. The following works have been accomplished: (1) the rock blasting process is analyzed theoretically, combined with the rock blasting process. The strain rate effect of rock under explosive dynamic load, the dynamic process of rock blasting and the superposition of explosion load and initial stress are analyzed. (2) the rock blasting process of spherical charge under initial stress is numerically simulated by LS-DYNA. The blasting funnel size under different resistance lines is compared. The results show that the blasting funnel formed under different resistance lines is very different. In the model calculated in this paper, the blasting funnel is the largest when the resistance line is W=20mm. The initial stress does not affect the propagation of the stress wave of the spherical charge, but it will inhibit the formation of the blasting funnel perpendicular to the direction of the initial stress, and the blasting process of the columnar charge rock under the initial stress is numerically simulated. The results show that the initial stress does not affect the propagation and attenuation of the explosive stress wave of the cylindrical charge, nor does it affect the formation of the blasting comminuted zone, but it inhibits the formation of cracks perpendicular to the initial stress direction. The blasting process of rock under initial unloading stress is numerically simulated. The results show that unloading stress wave can improve the distribution of stress field in rock. (3) numerical simulation of the blasting process under initial stress and pre-splitting blasting process is carried out by using LS-DYNA. The results show that when the distance between the holes is appropriate, the through-through cracks are formed between different holes. When the row hole is parallel to the initial stress, the effect of the row hole blasting is the best. When the row hole is perpendicular to the initial stress, the row hole blasting effect is the worst. Pre-cracking holes can induce the formation of cracks between two holes, and the blasting process of rock with joints under initial stress is numerically simulated. The results show that the joints can transmit and reflect the explosion stress waves, and make the rocks produce reflective tensile cracks. However, through joint hinders further crack propagation. When the angle between the local joint tip and the hole line and the local joint is small, the crack growth can be induced by the local joint tip. Numerical simulation of rock blasting process in hollow zone under initial stress is carried out. The results show that the empty zone provides free surface for blasting. The stress distribution and blasting effect in rock are improved. (4) numerical simulation of crack propagation process driven by explosion gas is carried out by using ABAQUS. The results show that with the crack propagation, the gas pressure decreases and the crack growth speed decreases. When the explosion gas pressure reaches the critical pressure, the crack growth stops, and the crack propagation process driven by the explosion gas under the initial stress is numerically simulated. The results show that the initial stress can suppress the crack propagation perpendicular to the initial stress direction. When the initial crack direction is the same as the initial stress direction or the initial stress resultant direction, the crack propagates along the original direction, otherwise, the crack tends to propagate in the direction of large initial stress.
【學位授予單位】：東北大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU45
本文編號：2169452
[Abstract]:Due to the decrease of shallow resources and the need of some projects, resource mining and tunnel excavation have entered deep underground. The deep rock mass is often in the environment of high initial in-situ stress. When blasting, the rock ruptures under the joint action of initial stress and explosion load. This process is very complicated and can not be analyzed by the blasting theory of shallow rock mass. Therefore, it is necessary to analyze the rock blasting process under initial stress. In this paper, the numerical simulation of rock blasting process under initial stress has been carried out by using finite element software LS-DYNA and ABAQUS. The following works have been accomplished: (1) the rock blasting process is analyzed theoretically, combined with the rock blasting process. The strain rate effect of rock under explosive dynamic load, the dynamic process of rock blasting and the superposition of explosion load and initial stress are analyzed. (2) the rock blasting process of spherical charge under initial stress is numerically simulated by LS-DYNA. The blasting funnel size under different resistance lines is compared. The results show that the blasting funnel formed under different resistance lines is very different. In the model calculated in this paper, the blasting funnel is the largest when the resistance line is W=20mm. The initial stress does not affect the propagation of the stress wave of the spherical charge, but it will inhibit the formation of the blasting funnel perpendicular to the direction of the initial stress, and the blasting process of the columnar charge rock under the initial stress is numerically simulated. The results show that the initial stress does not affect the propagation and attenuation of the explosive stress wave of the cylindrical charge, nor does it affect the formation of the blasting comminuted zone, but it inhibits the formation of cracks perpendicular to the initial stress direction. The blasting process of rock under initial unloading stress is numerically simulated. The results show that unloading stress wave can improve the distribution of stress field in rock. (3) numerical simulation of the blasting process under initial stress and pre-splitting blasting process is carried out by using LS-DYNA. The results show that when the distance between the holes is appropriate, the through-through cracks are formed between different holes. When the row hole is parallel to the initial stress, the effect of the row hole blasting is the best. When the row hole is perpendicular to the initial stress, the row hole blasting effect is the worst. Pre-cracking holes can induce the formation of cracks between two holes, and the blasting process of rock with joints under initial stress is numerically simulated. The results show that the joints can transmit and reflect the explosion stress waves, and make the rocks produce reflective tensile cracks. However, through joint hinders further crack propagation. When the angle between the local joint tip and the hole line and the local joint is small, the crack growth can be induced by the local joint tip. Numerical simulation of rock blasting process in hollow zone under initial stress is carried out. The results show that the empty zone provides free surface for blasting. The stress distribution and blasting effect in rock are improved. (4) numerical simulation of crack propagation process driven by explosion gas is carried out by using ABAQUS. The results show that with the crack propagation, the gas pressure decreases and the crack growth speed decreases. When the explosion gas pressure reaches the critical pressure, the crack growth stops, and the crack propagation process driven by the explosion gas under the initial stress is numerically simulated. The results show that the initial stress can suppress the crack propagation perpendicular to the initial stress direction. When the initial crack direction is the same as the initial stress direction or the initial stress resultant direction, the crack propagates along the original direction, otherwise, the crack tends to propagate in the direction of large initial stress.
【學位授予單位】：東北大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU45
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