广州地铁盾构施工端头预加固合理范围研究及应用

发布时间：2018-08-03 14:13

【摘要】：盾构施工具有机械化程度高、掘进速度快、施工安全性高、对周围环境影响小等优点,广泛应用于城市地铁、电力、市政等地下隧道建设中。在盾构法隧道施工中,盾构始发与到达施工是整个隧道施工的关键环节。如若施工不当,可能会发生如塌方、透水、端头土体土体失稳等安全问题。为了避免在盾构始发与到达施工过程中可能出现的一系列问题,需要对端头土体进行加固,以确保盾构隧道能够顺利始发与及时贯通。本文以广州市轨道交通九号线花都广场站~马鞍山公园站(简称花马区间)地铁隧道为工程背景,结合工程实际,运用工程经验、理论分析和数值模拟等方法,对地铁隧道盾构始发站(马鞍山公园站)端头土体加固的加固工法、加固理论、数值模拟进行了分析与研究。具体工作内容如下:(1)通过在广州轨道交通花马区间地铁隧道工程的实习,了解盾构始发工程的概况以及该项目盾构始发采用的加固方法与施工工艺,并在此基础上来理解各种端头加固工法的优缺点及其适用条件,把握盾构始发端头土体施工的重点、难点,藉以实现对地铁隧道盾构始发工程安全的有效控制;(2)在经典强度理论的基础上,通过建立端头加固土体的力学与数学模型,运用弹性力学、高等土力学和高等数学方法推导出端头土体的纵向、横向加固范围的理论解,并就马鞍山公园站的工程条件进行实际算例分析,为工程实际施工提供理论参考;(3)采用三维有限差分数值模拟软件FLAC3D,在盾构始发封门拆除最不利工况下,从位移场、破坏场、应力场出发,进行端头加固范围数值模拟。首先保证横向加固范围为3m,纵向加固长度依次取3m、6m、10m、15m进行模拟,以确定合理的纵向加固数值解;其次保证合理的纵向加固范围不变,横向加固范围依次取盾构两侧1m、2m、3m、4m范围进行模拟,以确定合理的横向加固范围,进一步为工程施工和理论研究提供参考性建议。主要研究成果如下:(1)马鞍山公园站盾构始发工程处于高水压砂层、上软下硬地层中,该地层具有渗透系数大、施工参数不好控制、地层承载能力差等特点。三重管高压旋喷桩加固法适用于砂土、砂卵石、淤泥及软弱黏性土等多种土层,形成的旋喷桩体强度高、耐久性好,另外其操作简单、可灌性好、材源广阔、价格低廉等诸多优点,适用于马鞍山公园站盾构始发工程的土体加固;(2)由弹性薄板理论、土体滑移失稳理论、土体扰动极限平衡理论和松动圈的相关知识及端头加固的构造分析,建立相应的力学计算模型;通过弹性力学、高等土力学相关知识及高等数学的解析方法,推导出端头土体加固范围的理论解,并就马鞍山公园站工程实例进行算例分析,结果表明,与实际加固相比而言纵向和隧道两侧相差不大,隧道拱底砂性土及拱底炭质灰沿土层计算有所偏差,主要原因可能是未考虑实际地质情况及加固土体等因素的影响。(3)由数值模拟结果可知:在综合考虑不同纵向、横向加固范围的位移场、破坏场和应力场以及盾构始发的止水性要求的前提下,结合实际工程地质条件和理论研究结果,最终确定本工程盾构始发端头土体加固为:纵向加固长度取10m,横向加固长度取3m,深度方向为隧道顶部加固取5m,隧道中心以下无加固。施工中只要确保工程质量,就可以满足盾构始发的强度和稳定性要求。(4)本研究对于广州地区地铁隧道盾构法施工或其它类似高水压砂性土、上软下硬地层施工条件的工程,具有一定的参考和应用推广价值。
[Abstract]:The shield construction has the advantages of high mechanization, fast driving speed, high construction safety and small influence on the surrounding environment. It is widely used in the construction of underground tunnels in urban subway, electric power, municipal and other underground tunnels. During the construction of shield tunneling, shield construction and construction are the key links of the whole tunnel construction. If improper construction, it may happen. In order to avoid a series of problems that may occur during the initiation and construction of the shield, it is necessary to reinforce the end soil in order to ensure the smooth start and the timely penetration of the shield tunnel. This article takes the Ma'anshan Park of Huadu Square Station in line nine of Guangzhou rail transit to Ma'anshan Park The subway tunnel is the engineering background. Combining engineering practice, engineering experience, theoretical analysis and numerical simulation, the reinforcement method, reinforcement theory and numerical simulation of metro tunnel shield starting station (Ma'anshan Park Station) end soil reinforcement are analyzed and studied. The concrete work contents are as follows: (1) through The practice of the metro tunnel project in Guangzhou rail transit is to understand the general situation of the shield construction project and the reinforcement method and construction technology adopted in this project, and to understand the advantages and disadvantages of all kinds of end reinforcement methods and their applicable conditions on this basis. The effective control of the safety of the shield construction of the subway tunnel is made. (2) on the basis of the classical strength theory, through the establishment of the mechanics and mathematical model of the end reinforcement soil, the theoretical solution of the longitudinal and transverse reinforcement range of the end soil body is derived by using the elastic mechanics, the higher soil mechanics and the higher mathematics method, and the work of the Ma'anshan Park station is worked out. The practical case analysis is carried out to provide theoretical reference for the actual construction of the project. (3) using the three-dimensional finite difference numerical simulation software FLAC3D, the numerical simulation of the end reinforcement range is carried out from the displacement field, the failure field and the stress field under the most unfavorable conditions of the shield opening door. First, the lateral reinforcement scope is guaranteed to be 3M, and the longitudinal reinforcement is long. The degree of 3M, 6m, 10m, 15m is simulated in order to determine the reasonable numerical solution of the longitudinal reinforcement. Secondly, the reasonable longitudinal reinforcement range is guaranteed. The lateral reinforcement range is taken in order to simulate the range of 1m, 2m, 3M and 4m on both sides of the shield, so as to determine the reasonable lateral reinforcement scope, and provide some reference suggestions for the engineering construction and the theoretical research. The research results are as follows: (1) the shield construction project in Ma'anshan Park station is in the high water pressure sand layer, in the upper soft and hard stratum, the stratum has the characteristics of large permeability coefficient, poor construction parameter control, poor bearing capacity of the formation and so on. The three heavy pipe high pressure jet grouting pile reinforcement method is suitable for sand soil, sand gravel, silt and soft clay soil and so on. The rotary jet pile has high strength, good durability, simple operation, good irrigability, wide material source, low price and so on. It is suitable for soil reinforcement of the shield construction project of Ma'anshan Park station. (2) the theory of elastic thin plate, the theory of soil slip instability, the related knowledge of the limit equilibrium theory of soil disturbance and the reinforcement of the end of the loose circle By structural analysis, the corresponding mechanical calculation model is set up, and the theoretical solution of the reinforcement range of the end soil is derived through the elastic mechanics, the knowledge of higher soil mechanics and the analytical method of higher mathematics, and the example of the Ma'anshan Park Station project is analyzed. The results show that the difference between the longitudinal and the two sides of the tunnel is small, compared with the actual reinforcement. There is a deviation in the calculation of the sandy soil and the carbonaceous ash at the bottom of the arch at the bottom of the tunnel. The main reason may be that there is no consideration of the actual geological conditions and the influence of the soil reinforcement. (3) it is known from the numerical simulation results that the displacement field, the broken field and stress field, and the water stop requirements of the shield originating from the different longitudinal and transverse reinforcement range are considered comprehensively. Under the premise, combined with the actual engineering geological conditions and theoretical research results, it is finally determined that the soil reinforcement at the beginning end of the shield is 10m, the length of lateral reinforcement is 3M, the depth direction is reinforced at the top of the tunnel, and 5m is reinforced at the top of the tunnel. The construction quality can be satisfied as long as the quality of the project is ensured. Strength and stability requirements. (4) this study has a certain reference and application value for the shield construction of subway tunnels in Guangzhou or other similar high water pressure sand soil, soft and hard stratum construction conditions.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U231.3;U455.43

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