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1.
Fractures developed around high pressurized gas or air storage tunnels can progressively extend to the ground surface, eventually leading to an uplift failure. A tool reasonably reproducing the failure patterns is necessary for stability assessment. In this study, a numerical method based on the element-free Galerkin (EFG) method with a cohesive crack model is developed to simulate fracture propagation patterns in the rock mass around a tunnel under high internal pressure. A series of physical model tests was also conducted to validate the reliability of the developed method. A qualitative agreement between physical model tests and numerical results can be obtained. The in situ stress ratio, k, has a strong influence on both the position of crack initiation and the propagation direction. The numerical analyses were extended to full-scale problems. Numerical tests were performed to investigate the prime influencing factors on the failure patterns of a high pressurized gas circular tunnel with varying parameters. The results suggest that initial in situ stress conditions with a high k (larger than 1) is favorable for construction of pressurized gas or air storage tunnels. 相似文献
2.
不同倾角节理组和锚固效应对岩体特性的影响 总被引：1，自引：0，他引：1
首先采用DDARF(discontinuous deformation analysis for rock failure)分析方法对双裂隙岩块进行单轴和双轴压缩模拟试验,研究了裂隙角度和侧向应力大小对岩块特性的影响,得到了裂隙岩块在这两种加载试验中的破坏过程、应力-应变曲线以及岩块中裂隙的起裂应力和岩块的峰值强度。在双轴压缩模拟试验中绘制了裂隙角度为45°的岩块在不同侧向压力下的强度包络线。其次,采用DDARF分析方法模拟劈裂试验中含裂隙试块的锚固效果,得到了4种不同锚固角度试块的轴向荷载–位移变化曲线和裂隙扩展规律。模拟结果与前人的类似条件下的试验结果相符良好。随后又将双裂隙试块双轴压缩模拟试验中得到的参数运用到一个地下洞室的工程实例中,用等效力学特性的方法分析对比了完整岩体和节理岩体洞室开挖完成后的破损状态的差异。最后运用DDARF分析方法研究了随机生成4组节理岩体的地下洞室的稳定性,得到了洞室节理围岩的裂隙扩展过程。同时通过对关键点位移的监测分析了锚杆的锚固效应。 相似文献
3.
为了研究含倾斜非盐夹层盐岩体的变形与破损特性,开展了含倾斜夹层盐岩试样的单轴、三轴压缩试验,并结合复合岩体破坏的理论分析,探讨了界面黏结应力的变化规律及其影响因素,揭示了倾斜层状盐岩体变形与破坏特征及其机制。研究表明,倾斜夹层对盐岩体的变形与破损具有显著影响。夹层各部破损形式与其所处位置有关;裂纹在界面处最先萌生、进而扩展到夹层和盐岩层;试验观察到盐斑的穿晶断裂现象并揭示了其力学机制;夹层厚度影响着盐岩体整体性能和破损特性,相对于薄夹层、中厚夹层更容易形成宏观裂纹;围压作用减少了夹层不同部位的破裂形态差异及界面黏结应力差异。该结果为含地层倾角盐岩矿区储气库的造腔优化及其稳定性、密闭性分析提供了理论参考,建议造腔前应优选地质层段,以同时满足稳定性和密闭性要求。 相似文献
4.
基于国内外研究现状和岩质滑坡案例,总结出岩质滑坡的水力致灾机制,归纳考虑水力作用下的岩质斜坡主要失稳破坏模式,评述了岩质斜坡稳定性分析方法。岩质滑坡的水力致灾机制主要由于水对滑体产生的静水压力（岩体侧面的推力、滑面的扬压力和岩体的浮力）和动水压力（向坡外的渗透力）作用。从渗流—应力耦合的角度可较全面评价水渗流对坡体稳定性的影响。斜坡的岩体结构决定了水力作用方式和坡体的失稳破坏形式,考虑水力作用下的岩质斜坡失稳破坏形式主要有:顺层滑动、平推式滑动、楔形体滑移和危岩的崩塌。对于水力作用下岩质斜坡的稳定性分析方法主要有极限平衡法、有限元强度折减法、基于断裂力学的危岩稳定性分析法和渗流—应力耦合模型分析法,其中前两种方法应用较为广泛。 相似文献
5.
通过系统分析边坡工程地质条件及岩体结构,采用定性分析结合有限元模拟研究了边坡变形破坏模式,并采用块体理论及极限平衡法系统分析边坡局部及整体稳定性。结果表明,切向边坡的变形破坏模式可以分为两类:深层变形破坏为受层间软弱夹层空间展布特征控制的块体失稳,浅表层破坏为局部块体失稳及强风化强卸荷带岩体沿最大剪应力带的滑移-拉裂变形。稳定性分析结果认为边坡浅表层岩体稳定性差,但发生深层破坏的可能性较小。 相似文献
6.
The rock around tunnels used for gas storage is subject to high pressures, reaching 30 MPa in the case of compressed air energy storage. Uplift failure of the overlaying rock mass up to the surface represents the main hazard scenario in such cases. The present paper investigates this problem by using the upper bound theorem of limit analysis assuming a continuum rock mass model obeying the Mohr Coulomb failure criterion with tension cut‐off. Tools of the calculus of variations are used to assess the geometry of the failure surface. The effects of geometrical and geotechnical parameters on uplift pressure are analyzed systematically. Charts are then provided, which enable a quick estimation of the upper bound of uplift pressure across a wide range of geotechnical and geometrical conditions. 相似文献
7.
井喷失控条件下盐岩储库稳定性分析 总被引：1，自引：0，他引：1
井喷压力失控是盐岩储气库运营的极端情况。根据一维绝热管流理论解析得到井喷情形下储库卸压规律。在此基础上结合金坛盐矿工程地质条件,模拟对比分析了不同初始内压失控工况下盐岩储库应力状态、变形收敛特征和损伤破坏规律。结果表明,溶腔硬夹层总是先于盐岩体而屈服形成明显的屈服带,失控卸压阶段塑性区逐渐扩展布满整个腔体并向径向延伸6～8 m;运营压力范围内初始内压越低,储库卸压收敛越大,7 MPa下储库体积损失达5.02%;卸压阶段溶腔内壁围岩应变速率跃升至10-2 s-1数量级,属于准静态范畴。研究认为,井喷失控状态下失控初始内压是维持储库腔体稳定性的关键因素,在极端灾害环境中应确保盐岩储库处于较高的运营压力之下 相似文献
8.
X. J. Li W. M. Yang L. G. Wang I. B. Butler 《Rock Mechanics and Rock Engineering》2014,47(6):2211-2223
Splitting failure, which is recognized as a special engineering geology phenomenon, occurs continually in the brittle rock mass of caverns during underground excavation. In this paper, a splitting model of linear slippage crack groups is built with fracture mechanics, energy analysis, and crack extension theories. Considering intrinsic cracks in rock mass and change of outer stress, intrinsic cracks propagate into macroscopical splitting cracks that are approximately parallel to the side wall of caverns. The splitting criterion of cavern rock mass and the method for predicting displacement in view of splitting opening displacement are proposed. In the end, the forecasting method is applied to the Jinping-I Hydropower Station, underground caverns engineering in China, the splitting failure zone and forecasting displacement are accordant with the monitoring data. The new forecasting displacement method is proven to contribute to the construction of similar underground caverns. 相似文献
9.
岩桥的破裂贯通是一种非连续变形现象。强度折减技术虽然是渐进破坏过程模拟的主流技术,但其不具备描述非连续变形现象的能力。提出连通率折减法和刚度折减法来模拟含非贯通结构面岩块的渐进破坏过程,并建立考虑渐进破坏过程的块体稳定分析方法。首先,引入Goodman单元来描述共面非贯通结构面的岩桥部分和裂隙面部分,建立静力平衡方程来求解滑裂面内岩桥单元和裂隙面单元的应力。其次,岩桥单元采用Griffith准则来判别破坏,利用连通率折减法来描述其破裂;裂隙面单元采用MC准则来判别破坏,用刚度折减法来描述其屈服;通过循环迭代,模拟岩桥单元的破裂过程和裂隙面单元的应力调整过程,实现整个滑裂面的渐进破坏过程模拟。然后,定义考虑渐进破坏过程的滑裂面极限状态;通过自重超载方式将滑裂面推送至极限状态;基于极限状态设计的理论框架,计算度量块体稳定性的安全系数指标。工程实例分析结果表明,渐进破坏过程模拟结果与现场调查结果是一致的。渐进破坏过程的模拟实现,有助于岩质边坡变形破坏机制分析从定性分析阶段扩展至定量分析阶段。 相似文献
10.
Fundamentals of gas containment in unlined rock caverns 总被引：3，自引：0，他引：3
Summary The criterion for gas entry into idealized, uniform, water-saturated fractures is examined for one-dimensional, elliptical and cylindrical cavern geometries. This limiting criterion is a necessary condition for gas escape from unlined, pressurized gas storages.Gas-entry phenomena were examined using 450-mm-square glass plates in Hele Shaw configuration with nominal apertures of 50 and 200 microns. The fundamentals of gas entry, as first enunciated by Åberg (1977), are confirmed by the experiments; the critical gas-entry pressure is a function of hydraulic flow regime, fracture-mouth capillarity and fracture-mouth profile. Finite-element simulation based on these fundamentals is substantiated by experimental observations and is therefore used for generalization.The gas-entry criterion is found to be sensitive to details of fracture geometry such as aperture, connection of the fractures to the groundwater regime, geometry of the intersection of the fractures with the gas cavern, disturbance of the rock mass as a consequence of excavation, and cavern shape. In view of the inability to predict or even measure these factors, an alternative criterion which ensures no gas migration away from the gas storage is proposed. This simple criterion insists that gas escape will not occur as long as the water pressure along all possible escape paths increases for some small distance in the direction of potential gas escape. This criterion is a generalization of Åberg's (1977) proposal that the vertical hydraulic gradient should exceed one for no gas escape. 相似文献
11.
针对我国须采用密集库群来提高油气地下存储中资源利用率的现状,对近置已有盐岩溶腔库群运营模式下储库稳定性和收缩变形展开了研究。基于声纳测腔成果,建立了符合实际存在的单腔模型及库群模型。对模拟结果进行了对比分析,明确了库群运行模式对储库稳定性的影响规律。发现储库相对位置和深度的差异、夹层地层倾角的存在、相邻储库体积和形状的不等同3个因素会导致某些腔体的收缩变形不对称、腔体形变不规则;不同于单腔的最大位移区域固定出现在腰部,库群模式下受周围腔体的影响,而并无固定的腔壁位移最大点位置;呈现板状存在贯穿整个库群的泥岩刚度大、蠕变性能低,并且其和盐岩交界面的抗剪能力较强,可以提高库群的整体性和稳定性;考虑地层倾角的夹层变形特性成为对库群密闭性不利的影响因素,泥岩-盐岩交接面的拉伸以及泥岩夹层本身的扭转弯曲会使泥岩层产生裂隙,贯通的裂隙可导致各个腔体失去独自运行的能力,影响储库运行效率 相似文献
12.
Ming Lu 《Engineering Geology》1998,49(3-4):353-361
A three-dimensional finite element analysis was performed to simulate field tests at a pilot gas storage project. The storage was a shallow rock cavern lined with a 6 mm thick steel liner. During the tests, high internal pressure up to 52 MPa was applied and deformation of both rock mass and the steel liner was recorded. The maximum rock displacements of less than 6 mm was numerically predicted and fits the measurement very well. The three-dimensional nonlinear finite element modeling has confirmed the overall stability of the structure and revealed the functioning of each structural component, including the rock mass, concrete lining and the steel liner. 相似文献
13.
盐岩地下储气库腔体以钻井水溶方式开采,溶腔形态可见性差、形态发展可控性难度高,针对畸形溶腔进行科学的稳定性评价是保证其安全运营的重要手段。将变权和相对差异函数理论引入到盐岩溶腔的安全评价中,建立适用于盐穴储气库畸形单腔的稳定性评价模型,首次以溶腔声纳测腔数据为基础,建立三维真实仿真模型并进行数值模拟,将数值模拟结果作为评价指标的评分依据,最后应用该方法对金坛储气库某腔体进行稳定性评价,并针对评价结果提出安全改善措施。研究结果表明,用变权方法对评价指标权重进行处理后得到的结果更加合理,通过将该方法与其他安全评价方法计算结果进行对比,证明了该模型在盐岩储气库畸形溶腔的稳定性评价中具有较好的适用性。 相似文献
14.
The main objective of this study is to evaluate the influence of blast-induced acceleration on the stability of slopes at
Arakli-Tasonu limestone quarry where a planar shear failure has recently been observed. The planar failure occurred within
rock layers consisting of limestone and clayey limestone. The triggering mechanism of the planar shear failure was investigated
using blast-induced acceleration values obtained from 73 shots, field measurements, laboratory assessment of rock material
properties and utilizing limit equilibrium analysis. From the analysis of slope stability, the safety factor at a magnitude
of 0.106g was found to be lower than a minimum value of 1.2 in the case of a water-filled tension crack of a slope, 15 m depth. These
findings indicate that the planar shear failure was strongly influenced by the acceleration of uncontrolled blasting operations
as well as heavy rainfall. 相似文献
15.
层状盐岩中储备库油气渗漏风险的故障树分析 总被引：1，自引：0，他引：1
油气渗漏是盐岩地下储备库事故的重要类型之一,具有突发性强、损失难以估计的特点。针对国内层状盐岩中储备库运营过程中的油气渗漏风险进行分析,揭示了油气渗漏事故的发生机制并建立了相应的故障树模型。通过对该模型的分析,找出了事故发生的各基本致因事件和故障模式,并得出适用于典型层状盐岩储备库油气渗漏事故的发生概率公式。分析结果表明,国内层状盐岩中储备库发生油气渗漏事故的可能故障模式有28种,且发生条件易于满足而难于防范,因此事故发生的可能性较大;按照各基本事件结构重要度的计算结果,盐岩强度低、盐岩蠕变过量、附近有断层、地震、造腔参数控制不当、非均匀地应力、人为操作失误等是层状盐岩中储备库油气渗漏事故的主要致因事件,并据此提出有效措施防止事故发生;通过专家调查法和故障树法的综合分析得出,金坛盐矿5口老腔储库在近10年的运营期内发生油气渗漏事故的概率为0.703%,属于偶发性事故。 相似文献
16.
加载速率对裂隙岩体的力学性质及变形破坏均有重要影响。利用二维颗粒流程序PFC2D开展了不同倾角非贯通单裂隙砂岩试件的单轴压缩试验,研究了中等应变率对裂隙砂岩应力-应变曲线特征、裂隙尖端应力状态、特征应力状态、岩体损伤及裂隙扩展等力学响应的影响规律。裂隙岩体应力-应变曲线呈现明显的波动性,定义应力突变指标 对应力突变型波动剧烈程度进行了定量统计分析：随应变率的增加,曲线应力突变波动越剧烈,且峰后明显大于峰前;随裂隙倾角的增大,波动幅度峰前增大,而峰后减小。裂隙尖端破裂应力随应变率增大均有所提高,随裂隙倾角的增大,切向剪应力 总体上呈增加变化,而法向应力 明显减小。尖端破裂时岩样加载应力 、岩样临界扩容应力 及峰值应力 均随应变率增大而增大。裂隙尖端的破裂可立即引起岩体扩容,一般应变率越低,岩体裂隙尖端破裂点 和扩容点 越接近峰值强度 。随着应变率的提高,损伤裂纹及宏观裂隙类型越多,岩体试件损伤破裂程度越强,特别是试件端部效应愈显著。裂隙首先以I型翼裂纹在其尖端起裂,而I型翼裂纹的扩展长度与加载速率与裂隙倾角具有较强的相关性。 相似文献
17.
Stability Analysis of the 19A Ore Pass at Brunswick Mine Using a Two-Stage Numerical Modeling Approach 总被引：1，自引：0，他引：1
Kamran Esmaieli John Hadjigeorgiou Martin Grenon 《Rock Mechanics and Rock Engineering》2013,46(6):1323-1338
The longevity of ore pass systems is an important consideration in underground mines. This is controlled to a degree by the structural stability of an ore pass which can be compromised by changes in the stress regime and the degree of fracturing of the rock mass. A failure mechanism specific to ore pass systems is damage on the ore pass wall by impact load or wear by material flow. Structural, stress and material flow-induced failure mechanisms interact with severe repercussions, although in most cases one mechanism is more dominant. This paper aims to provide a better understanding of the interaction of ore pass failure mechanisms in an operating mine. This can provide an aid in the design of ore pass systems. A two-stage numerical approach was used for the back analysis of an ore pass at Brunswick mine in Canada. The first stage in the analysis relied on a 3D boundary element analysis to define the stress regime in the vicinity of the ore pass. The second stage used a synthetic rock mass (SRM) model, constructed from a discrete fracture network, generated from quantitative rock mass field data. The fracture network geometry was introduced into a bonded particle model, in a particle flow code (PFC). Subsequently, the ore pass was excavated within the SRM model. A stability analysis quantified the extent of rock mass failure around the ore pass due to the interaction of pre-existing fractures and the failure of the intact rock bridges between these fractures. The resulting asymmetric failure patterns along the length of the ore pass were controlled to a large degree by the in situ fractures. The influence of particle flow impact was integrated into the model by projecting a discrete rock fragment against the ore pass walls represented by the SRM model. The numerical results illustrated that material impact on ore pass walls resulted in localised damage and accelerated the stress-induced failure. 相似文献
18.
为全面探究土岩组合岩体中抗拔桩的极限承载力,结合工程岩土参数及试验数据,运用Flac3D数值分析软件对其进行数值模拟分析,即可得到土岩组合岩体中抗拔桩的极限承载力。基于被动状态下的Kotter极限平衡方程式求解土层提供的抗拔力,根据岩石强度,基于Hoek-Brown破坏准则求解抗拔桩嵌岩端岩体的抗拉强度,从而可计算得到嵌岩端岩体的抗拔力;由静力平衡原理,叠加土层及嵌岩端岩体提供的抗拔力及破坏锥体重量,即可得到土岩组合岩体中嵌岩抗拔桩的极限承载力理论解析式。在嵌岩深度较小的情况下,该解析式的理论计算值与数值模拟分析值相接近,但随着嵌岩深度的增加,理论计算值会偏离数值计算值。故结合数值模拟试验值,对提出的极限承载力理论解析式作进一步的修正,得到修正后的极限承载力解析式能反映嵌岩端岩石风化程度、嵌岩深度、土层厚度、桩长对极限承载力的影响。运用修正后的解析式对该地质条件下不同抗拔桩的极限承载力计算表明：数值模拟结果与理论计算结果相吻合,说明所建立的抗拔桩极限承载力解析式的方法是可行的。同时,运用该方法可确定类似工程中嵌岩抗拔桩的极限承载力。 相似文献
19.
考虑岩石闭合裂纹壁面间存在的摩擦力对裂纹尖端应力场的影响,应用最大周向应力理论得到压剪复合裂纹的断裂角。在此基础上,依据岩石裂纹尖端双向受力时的破坏特征,结合最大周向应力准则与修正的格里菲斯（Griffith）强度理论,建立了考虑摩擦效应的闭合裂纹失稳扩展的岩石压剪断裂判据。研究结果表明：断裂角受裂纹和荷载方向的夹角、裂纹壁面之间的摩擦系数、侧压力系数的影响;当压剪裂纹的断裂角是某个定值时,纯II型裂纹的断裂韧度与纯I型裂纹的断裂韧度的比值只与岩石裂纹表面的摩擦系数取值有关,而与其他岩石力学参数无关。此研究成果可为压剪应力作用下裂隙岩体的失稳破坏提供参考。 相似文献
20.
The use of gas‐storage caverns in salt formations is a growing industry that continues to gain momentum because it allows gas to be injected and withdrawn at high rates compared with other underground gas‐storage systems such as porous rock systems. In order to predict cavern production performances, cavern thermodynamics behaviour must be studied by higher accuracy approaches. This behaviour is extremely related to the temperature distribution in the surrounding formations. During the leaching process, the thermal equilibrium of the rock salt surrounding the cavern is extensively disrupted. The purpose of this paper is to study the heat transfer problem during the leaching process and to develop a thermal model that can be easily used in field applications. The results of this work will be the input data for the prediction of the gas temperature and pressure during cavern gas‐storage operation phase. Moreover, the developed model can find its use in the design of salt caverns since it can be coupled with geometrical modelling of salt dissolution codes. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献