水工隧洞围岩渗流场和应力场数值模拟与分析

发布时间：2018-05-05 04:36

本文选题：隧洞 + 渗流场　；参考：《西安理工大学》2017年硕士论文

【摘要】：隧洞的开挖和施工经过的地质条件往往比较复杂,极有可能发生严重的工程事故,如突涌水、地表沉陷、洞身坍塌等,造成的工程人员伤亡、设备破坏、工期延误等将对工程建设带来很大的损失。隧洞建设中,地质灾害是在各种复杂的水文地质条件下形成的,研究隧洞围岩的应力场和渗流场有助于了解地质灾害产生的成因。本文在介绍裂隙岩体渗流基础理论的基础上,采用ADINA有限元软件进行了水工隧洞开挖的数值模拟,分析了渗流场和应力场在隧洞开挖前后的变化规律,研究了地下水水位和注浆圈对隧洞围岩中渗流场和应力场的影响,最后结合实际工程研究了应力场和渗流场随隧洞开挖时间的变化规律。本文主要得到以下几点结论:(1)隧洞开挖导致隧洞围岩中的地下水向洞内渗流,渗流场发生较大变化,隧洞周围产生明显的漏斗状的低孔隙水压力分布区。隧洞开挖后隧洞周边渗流速度和水力坡降比较大,不利于围岩的稳定。在隧洞周围注浆之后,隧洞周边孔隙水压力得到明显的回升,渗流速度大大减小,注浆效果十分明显。(2)隧洞开挖引起岩体明显的卸荷作用,在隧洞周围引起不同程度的低应力区,其中在拱顶和拱底周围应力降幅最大,有受拉趋势,在椒溪河隧洞的拱顶和拱底位置产生了拉应力区,验证了这一点。注浆后围岩整体应力得到改善,但在注浆圈与围岩交界处易出现应力集中现象。(3)地下水位对渗流场的影响主要表现在数值上,地下水位越高隧洞周边的渗流越大,但不同地下水位渗流场的分布规律具有很大的相似性。注浆圈能很好的降低围岩中的渗流速度,随着注浆圈厚度的增大,围岩渗流速度明显降低。地下水位越高对应力场的影响越大,注浆圈厚度越大,对于防止围岩出现过大变形,维护围岩的稳定性越有利。(4)对椒溪河隧洞进行了开挖数值模拟,分析了渗流场和应力场在开挖前后的变化,得出了隧洞开挖过程中围岩的孔隙水压力、流速、应力和位移随开挖时间的变化规律。
[Abstract]:The geological conditions through which the tunnel is excavated and constructed are often quite complicated, and serious engineering accidents are likely to occur, such as sudden water gushing, surface subsidence, hole collapse, etc., resulting in casualties and equipment destruction among engineers. The delay in the construction period will bring great losses to the project construction. In tunnel construction, geological hazards are formed under various complicated hydrogeological conditions. Studying the stress field and seepage field of surrounding rock is helpful to understand the causes of geological disasters. On the basis of introducing the basic theory of seepage in fractured rock mass, the numerical simulation of hydraulic tunnel excavation is carried out by using ADINA finite element software, and the variation law of seepage field and stress field before and after tunnel excavation is analyzed. The influence of groundwater level and grouting circle on seepage field and stress field in surrounding rock of tunnel is studied. Finally, the variation of stress field and seepage field with tunnel excavation time is studied in combination with practical engineering. The main conclusions of this paper are as follows: (1) the excavation of the tunnel leads to the seepage of groundwater in the surrounding rock of the tunnel into the tunnel, the seepage field changes greatly, and there is an obvious funnel-shaped low pore water pressure distribution area around the tunnel. After tunnel excavation, the seepage velocity and hydraulic gradient around the tunnel are relatively large, which is not conducive to the stability of surrounding rock. After grouting around the tunnel, the pore water pressure around the tunnel is obviously increased, the seepage velocity is greatly reduced, and the grouting effect is very obvious. Around the tunnel, there are low stress areas to different degrees, in which the stress decrease is the largest around the arch roof and the arch bottom, and there is a tendency of tension. The tensile stress zone is produced at the arch top and arch bottom position of the tunnel in Jioxihe River, which proves this point. After grouting, the overall stress of surrounding rock is improved, but the stress concentration phenomenon is easy to appear at the junction of grouting circle and surrounding rock.) the influence of groundwater level on seepage field is mainly expressed in numerical value, the higher the groundwater level is, the greater the seepage around the tunnel is. But the distribution law of seepage field of different groundwater level is very similar. The grouting ring can reduce the seepage velocity in the surrounding rock well, and with the increase of the thickness of the grouting ring, the seepage velocity of the surrounding rock decreases obviously. The higher the groundwater level, the greater the influence of the corresponding force field, the thicker the grouting circle, the more favorable the stability of the surrounding rock is to prevent the deformation of surrounding rock, and the more favorable to maintain the stability of surrounding rock, the numerical simulation of the excavation of the Jiaoxihe tunnel is carried out. The variation of seepage field and stress field before and after excavation is analyzed, and the variation law of pore water pressure, velocity, stress and displacement of surrounding rock during tunnel excavation with excavation time is obtained.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV554

【参考文献】