隧道泥质充填断层破碎带劈裂注浆扩散机理及工程应用

发布时间：2018-10-26 14:45

【摘要】：我国隧道工程建设发展迅速,其修建过程常揭露断层、岩溶等不良地质条件,尤其是富水软弱断层破碎带极易造成隧道施工期突水突泥等地质灾害,是影响隧道工程施工安全的重要因素。目前隧道施工期突水突泥灾害治理的主要工程技术方法是注浆,但是由于岩体介质与浆液及其相互作用机制极为复杂,注浆理论研究远滞后于工程实践,特别是针对富水软弱地层的注浆扩散理论和加固机理研究还处于初步探索阶段,尚未形成系统的理论,导致注浆方案设计和施工的盲目性和经验性较强,亟需系统科学的理论指导。本文以隧道突水突泥灾害的注浆治理理论和技术为研究目标,重点研究了浆液在断层泥质充填介质中的劈裂扩散理论,同时研究了浆液在断层过水断面和断层结构面中的扩散机理,最后考虑综合工况和介质条件,研究了在劈裂、渗透和挤密综合作用下的围岩加固机理,提出了注浆加固圈厚度的优选方法。基于本文研究提出了富水泥质充填断层破碎带突水突泥灾害治理关键技术,并在江西省吉莲高速公路永莲隧道F2断层突水突泥灾害治理中成功应用。(1)研究了浆液在断层泥质充填介质中的劈裂扩散理论,将劈裂注浆过程作为以注浆孔为中心的水平辐射圆,推导了劈裂通道内部的浆液扩散运动方程。引入断裂力学理论,建立了裂缝表面非线性分布压力下的轴对称空间圆片状裂缝理论模型,最终得到劈裂通道宽度的空间分布及注浆压力的空间衰减方程。分析了劈裂通道宽度及注浆压力的空间衰减规律及浆液参数、土体力学参数对浆液扩散过程的影响。(2)为研究浆液在泥质充填断层破碎带软弱结构面内的扩散规律,设计了一套可变倾角单一结构面注浆扩散模型试验系统,将断层带结构面简化为单一平板结构面,并设计了模拟其各向异性的多种结构面角度,开展了45组可变倾角单一结构面注浆模型试验。并得出如下结论,浆液在水平结构面中呈“U型”规律；在一定倾角结构面中,浆液扩散形态呈现“彗星状”。(3)设计了一套三维断层注浆模型试验装置,由主体介质填充版块、注浆版块、注浆信息采集版块、图像信息实时采集版块和高压密封版块构成,可以充填原位断层介质,具备三维条件下的断层高压注浆模型试验功能。试验发现,浆液以劈裂为主、挤密和充填为辅的联合作用型式加固断层介质,注浆过程中压力和速率均呈震荡变化特征；渗透压力和土压力在注浆过程中响应明显,随着注浆次数的增加有一定波动规律,但总体呈逐渐上升趋势。(4)基于流固耦合理论,考虑隧道开挖过程中渗流场与应力场的相互影响,建立相应的有限元模型,研究注浆加固圈的存在对隧道围岩应力场、位移场、渗流场的影响,并通过隧道涌水量及隧道变形量随注浆加固圈厚度的变化规律研究,对注浆加固圈厚度进行优选。最终确定了永莲隧道帷幕注浆工程注浆加固圈最优厚度。(5)针对依托工程F2断层突水突泥灾害中突泥量大,水压高,揭露水量大,补给充分等特点,以断层软弱介质的注浆扩散和加固理论为指导,提出了恒定终压阶梯式控制注浆技术及设计方法。采用阶梯式控制注浆速率方式,结合注浆孔揭露含水体涌水量和水压,及时动态调整钻孔引排泄压,有效防止高压封闭水体出现,保障注浆加固过程的安全。研究成果在江西吉莲高速永莲隧道F2断层突水突泥灾害注浆综合处治工程中进行了现场试验,取得了良好的治理效果,具有广阔的工程推广价值。
[Abstract]:With the rapid development of tunnel engineering construction in China, the construction process often reveals the bad geological conditions such as fault and karst, especially the water-rich weak fault fracture zone, which can easily cause geological disasters such as water inrush from the construction period, and is an important factor affecting the construction safety of tunnel construction. At present, the main engineering technique for the prevention and treatment of water outburst in the construction period of the tunnel is grouting, but because the rock mass medium and the slurry and its interaction mechanism are very complicated, the research of grouting theory lags far behind the engineering practice, Especially, the research on grouting diffusion theory and reinforcement mechanism of water-rich weak stratum is still in the preliminary exploration stage, yet the theory of the system has not been formed, which leads to the blindness and experience of the grouting scheme design and construction, and the theoretical guidance of the system science is urgently needed. In this paper, the theory and technology of grouting are studied in this paper, and the split diffusion theory of slurry in fault-mud filling medium is studied, and the diffusion mechanism of slurry in the cross-section of fault and the surface of fault structure is studied. Finally, considering the comprehensive working condition and medium condition, the paper studies the strengthening mechanism of surrounding rock under the comprehensive action of splitting, seepage and compaction, and puts forward the preferred method of grouting reinforcement ring thickness. Based on the research of this paper, the key technologies for the treatment of water-process mud disaster are put forward in this paper, and the successful application of Fulian tunnel F2 fault treatment in Jiulian expressway, Jiangxi Province, has been put forward. (1) The split diffusion theory of slurry in fault mud filling medium is studied, and the split grouting process is used as the horizontal radiation circle centered on the grouting hole, and the equation of slurry diffusion motion inside the split channel is derived. By introducing the theory of fracture mechanics, the theoretical model of axisymmetric space circular sheet crack under nonlinear distribution pressure of fracture surface is established, and the spatial distribution of split channel width and the spatial attenuation equation of grouting pressure are finally obtained. The spatial attenuation law and slurry parameters of split channel width and grouting pressure are analyzed, and the influence of soil mechanics parameters on the process of slurry diffusion is analyzed. (2) In order to study the diffusion law of slurry in the weak structural plane of mud-filled fault fracture zone, a set of single-structure surface grouting diffusion model test system with a variable inclination angle is designed, which simplifies the structure surface of the fault belt into a single plane structure plane. In this paper, a multi-structural plane model is designed to simulate its anisotropy, and a single-structure surface grouting model test of 45 sets of variable inclination angles is carried out. It is concluded that the slurry is U-shaped in the horizontal structural plane, and in a certain angle of inclination, the shape of the slurry diffuses into a comet-like shape. (3) a set of three-dimensional fault grouting model test device is designed, and has the function of a fault high-pressure grouting model test under three-dimensional conditions. It is found that the pressure and velocity in the grouting process are characterized by vibration change, and the osmotic pressure and soil pressure are obvious during the grouting process. With the increase of the number of grouting, there is a certain fluctuation rule. But there is a trend of gradual upward trend. (4) Based on the theory of flow-solid coupling, considering the interaction between seepage field and stress field during tunnel excavation, a corresponding finite element model is established to study the influence of grouting reinforcement ring on stress field, displacement field and seepage field of surrounding rock. and the thickness of the grouting reinforcement ring is optimized according to the change rule of the thickness of the grouting reinforcement ring through the tunnel water inflow and the deformation amount of the tunnel. Finally, the optimal thickness of grouting reinforcement ring for the curtain grouting project of Yong-lian tunnel is determined. (5) According to the characteristics of large amount of outburst mud, high water pressure, large exposed water quantity and sufficient recharge, the grouting technology and design method of constant end pressure step control are put forward aiming at the characteristics of large amount of outburst mud, high water pressure, large exposed water quantity and sufficient recharge. According to the step type control grouting rate mode, the water inflow amount and the water pressure of the water body are exposed in combination with the grouting holes, the drilling drainage pressure is dynamically adjusted, the high-pressure closed water body is effectively prevented, and the safety of the grouting reinforcement process is guaranteed. In this paper, the field tests were carried out in the comprehensive treatment project of the F2 fault outburst of the high-speed Yong-lian tunnel of Jiulian, Jiangxi Province, and the good governance effect was obtained, and the project has wide engineering popularization value.
【学位授予单位】：长沙理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U455.49

【相似文献】