双侧壁导坑法标准化施工研究

发布时间：2018-06-10 20:56

  本文选题：浅埋段隧道 + 双侧壁　； 参考：《华南理工大学》2015年硕士论文

【摘要】：隧道洞口浅埋段一般岩体破碎,稳定性差,施工风险高,大断面隧道一般均采用双侧壁导坑法开挖,以控制围岩变形与松弛,确保隧道整体稳定与支护受力安全。双侧壁导坑法首先源自德国,曾在德国地铁中成功应用,目前是我国在浅埋地形、软弱地层中修建大断面地下工程时普遍采用的一种工法,已经在公路、铁路、城市地铁隧道建设中获得广泛应用,积累了大量实践经验。尽管如此,我国在采用双侧壁导坑法进行洞口浅埋段施工时仍出现了许多安全事故,如隧道冒顶坍塌、掉块、喷射混凝土开裂、锚杆失效、地表开裂与下沉、钢拱架严重扭曲变形等。这些安全事故的发生,一方面与施工管理与安全措施不到位有关,另外一方面则与双侧壁导坑法的工艺流程与标准不统一有密切关系。本文结合工程实例中大断面扁平隧道的实际洞形大小与围岩状况,采用大型岩土工程软件FLAC3D进行数值模拟,重点对中隔壁曲率半径、侧壁导坑的大小(中隔壁位置)、中导洞分块大小等三个关键工序参数进行平面应变模式下的标准化施工研究,分别将中隔壁曲率半径分为R=11.6m∠52°、R=5.76m∠106°、R=5.46m∠104°以及R=+∞∠180。四种工况；将侧壁导坑的大小(中隔壁位置)分为L=1/3B、L=1/4B和L=1/5B三种工况；将中导洞分块大小分为h1=1/2H(两台阶)、h,=1/3H(两台阶)、h1=3/5H(跟最大断面处、两台阶相对应)、h1=h2=1/3H(三台阶)四种工况进行仿真模拟分析,通过对围岩沉降、水平位移、围岩塑性区、围岩最大压应力、围岩最大拉应力、初期支护最大压应力、初期支护最大拉应力七个指标的比较进行综合必选,确定最优的参数取值,从而提出双侧壁导坑法标准化施工方案。
[Abstract]:In order to control the deformation and relaxation of surrounding rock and to ensure the overall stability and safety of the tunnel, large section tunnels are generally excavated by the method of double-sidewall diversion pit with poor stability and high construction risk. The method of double-sidewall pit guide first originated in Germany and was successfully applied in the German subway. At present, it is commonly used in the construction of large cross-section underground projects in shallow buried terrain and soft strata in China. It has already been used in highways and railways. Urban subway tunnel construction has been widely used, accumulated a lot of practical experience. However, there are still many safety accidents such as tunnel roof collapse, falling block, shotcrete cracking, bolt failure, surface cracking and subsidence, when using double-side wall guide pit method to carry out shallow burying section construction of the tunnel, such as tunnel roof collapse, block fall, shotcrete cracking, bolt failure, ground surface cracking and subsidence, etc. Severe distortion of steel arch, etc. The occurrence of these safety accidents is related to the lack of construction management and safety measures on the one hand, and to the disunity of the technological process and standard of the double-sidewall guide pit method on the other hand. Combined with the actual hole size and surrounding rock condition of large section flat tunnel in engineering example, the numerical simulation of large geotechnical engineering software FLAC3D is carried out in this paper, with emphasis on the radius of curvature of the middle and next section. Three key process parameters, namely, the size of the sidewall guide pit (the middle adjoining position and the block size of the middle guide tunnel), are studied in the standardized construction under the plane strain mode. The radius of the curvature of the middle wall is divided into two categories: r = 11.6m ~ 52 掳, R ~ (5.76 m) ~ 106 掳~ (?) ~ (5.46m) ~ 104 掳and R = 鈭，

本文编号：2004614