【作者】 黄明琦；

【导师】 王渭明；

【作者基本信息】 山东科技大学 ， 岩土工程， 2008， 博士

【摘要】 本论文结合中国大陆第一座海底隧道——厦门翔安海底隧道施工,以陆域、浅滩段软弱围岩施工稳定性控制为主线,以保护围岩自稳和指导施工为目的,从地质因素和岩体力学方面评价陆域、浅滩段围岩稳定性。通过室内试验、现场监测、数值计算和理论分析,分别对陆域浅滩段CRD工法和CD工法沉降控制对比、CRD工法步距和步序沉降控制作用、变形分配控制原理及应用、锁脚锚杆作用机理数值模拟分析、软弱地层充填注浆沉降控制等进行研究。利用数值方法,模拟现场土层条件和施工条件,对CD工法和CRD工法分别建模计算,对这两种工法进行数值模拟分析和比较,综合考虑进度、经济、安全等因素,对施工方法进行比选和优选,确定合理的施工方法——CRD施工方法;对CRD工法施工步距和步序进行优化,改进隧道开挖支护方案,将拱顶沉降控制在最小范围内,解决了施工中的技术难题。将变形分配控制原理应用于翔安隧道施工。首先,通过数值计算和工程经验确定控制的目标值;其次,通过监测确定隧道相应部位的变形信息,与确定的控制目标值对照,随时了解结构变位发展情况;最后,分析过度变位原因,制定相应对策,及时采取措施,修改施工方案,确保施工累计变位小于分步变位累计管理值;在系统研究锁脚锚杆作用机理的基础上,结合厦门海底隧道软弱破碎围岩地段锁脚锚杆的实际施工状况,建立锁脚锚杆力学分析模型,考虑锁脚锚杆在不同打入角度、有无注浆、设置垫块与否等因素,对拱顶下沉量进行数值模拟,并结合现场监测,对工作面开挖扰动区应力、位移场进行分析,系统地研究了锁脚锚杆受力和变形规律。据此分析了各影响因素与拱顶沉降的关系,优化锁脚锚杆的设计和施工方法;利用初支刚度和围岩的弱化刚度模量研究围岩的突变失稳,建立初支和围岩相互作用的突变模型,研究结果从理论上解释了壁后注浆加固机理。突变模型定量的给出了突变失稳的关键点,当围岩变形量超过关键点后,围岩就进入了散体区。变形关键点的大小是由围岩—初支系统内部因素决定的,和外界条件无关,因而应根据围岩和初支的具体情况,进行壁后注浆的设计和施工。初支背后充填注浆,加固围岩,提高围岩和初支的承载力和自稳力,控制沉降和变形。壁后注浆沉降控制作用从现场监测的数据得到很好的验证。厦门翔安海底隧道是中国海底隧道建设的开端,本文结合第一条海底隧道的施工过程、监控量测、数值模拟对隧道施工稳定性控制进行研究,取得的成果指导后续海底隧道的建设。更多还原

【Abstract】 This dissertation combines the construction process of Xiamen Xiang’an subsea tunnel. Based on the main study course of stability control of the surrounding rock in the shallow shoal and shore, the aim is to maintain the rock self-stability and guide the construction, Contrast of the sedimentation in CRD and CD construction method in weak strata of the shallow shoal and shore; Analysis different sedimentation caused by different step distance and sequence in CRD method; Study on the displacement dividing principle and its use; Numerical simulation of the mechanism of the feet-lock bolt; Study on the effect of distortion control by radial grouting behind the initial shoring in large-section tunnel in weak surrounding rock.Setting up models and caculating for CD and CRD method according to simulating the conditions of the site strata and construction by using numerical simulation, selecting the suitable construction method for large section subsea tunnels based on analyzing and the result comparision, considering intergrational factors include the plan, economic and safety. Based on CRD method, optimizing the construction sequence and step distance, mending the excavation and shoring scheme and control the distortion to the minimum value and conquering the construction difficuilties.Using the displacement dividing principle in Xiamen Xiang’an subsea tunnel. First, selecting target value of the distortion according to numerical caculating. Second, commanding the progress of the distortion of the tunnel and comparing the distortion with the target value. Last, analyzing and finding out the reason of over-distortion and giving the control measures and making sure the adding up distortion value not exceeding the target value.Setting up the analyzing model of the mechanics of the feet-lock bolt by systemic study of the working mechanism of the feet-lock bolt, analyzing the relationship of the top arch sedimentation and the influence factor, optimizing the design and construction method of the feet-lock bolt.Studying the mutational breakage through the stiffness of the initial timbering and the weaken stiffness of the surrounding rock and by setting up the interactional mutation model of the initial timbering and the surrounding rock. And the result of the study explains the mechanism of the reinforcement of the grouting on the back of the initial timbering and giving the key point of the mutation. After the distortion exceeds the key point the surrounding rock will coming into the incompact state. the size of the key point of the distortion is decided by the inner factors—the surrounding wall and the initial timbering and had no relation to out side conditions, so the design and construction of the grouting should be based on the material conditions of the initial timbering and the surrounding rock. The distortion was controlled well tested by the monitoring data.Xiamen Xiang’an subsea tunnel is the beginning of subsea tunnel construction in China. The fruit achieved from the study of the stability control, the site working monitoring and numerical caculatiing will guide the incoming subsea tunnel building.更多还原