南水北调东干渠某标段土压平衡盾构施工关键技术研究
发布时间：2018-10-12 08:55
【摘要】：随着我国城市隧道工程的迅速发展,土压平衡盾构法以施工速度快、劳动强度低、对环境影响小、施工经济等优点得到了广泛的应用,成为软土地基隧道施工的首选,并在技术和经济上取得了良好的效果。但是在土压平衡盾构施工过程中仍然存在着一些问题,如盾构机推进速度、推力、舱内土压、刀盘转速、出土量和螺旋输送机转速间的相互关系、刀盘阻塞及出土不畅、土仓压力如何取值才能使掌子面保持平衡、同步注浆压力与注浆量控制、施工过程中的地层位移等。本文以北京市南水北调东干渠某标段土压平衡盾构施工为工程背景,对施工过程中开挖渣土改良、掌子面压力取值和地层位移变化规律进行了研究。具体研究内容及获得的结论如下:①渣土改良实验。设计了一系列渣土改良室内试验,分别对细中砂和粉质粘土进行土体改良优化试验,得到细中砂最佳泡沫注入比为8%,粉质粘土的最佳泡沫注入比为30%,并根据现场混合地层细中砂和粉质粘土的体积不同确定最佳泡沫注入比参数为22%。②掌子面压力理论计算。运用不同的土仓压力计算理论,得到优化后盾构开挖面压力取值范围为100-150KPa。③地层位移变化监测。对地表位移、土体竖向位移、土体水平位移和盾构机实时工作参数进行了监测。得到地层竖向位移变化过程分为三个阶段,隆起阶段、快速沉降阶段、缓慢沉降阶段;隧道方向水平位移变化也分为三个阶段,先向盾构前进方向变化、然后再反方向变化、最后又向盾构前进方向变化;盾构机总推力、土仓压力和刀盘扭矩成正相关关系,盾构参数的变化对地层位移有着明显的影响。④地层位移变化数值模拟。本文运用FLAC3D软件对实际监测段盾构施工过程地层位移变化进行数值模拟计算。模拟得到的地层位移变化规律与实际位移变化规律相似。本文的结论对实际工程具有参考意义,可以为类似地层土压平衡盾构施工提供借鉴。
[Abstract]:With the rapid development of urban tunnel engineering in China, the earth pressure balance shield method has been widely used in the construction of soft ground tunnel with the advantages of fast construction speed, low labor intensity, small environmental impact and construction economy. And achieved good results in technology and economy. However, there are still some problems in the construction of earth pressure balance shield machine, such as the speed of shield machine, the thrust, the earth pressure in the cabin, the rotation speed of the cutter head, the relationship between the unearthed quantity and the rotating speed of the screw conveyor, the blocking of the cutter head and the unobstructed excavations. How to choose the value of soil pressure can keep the balance of face surface, control the grouting pressure and grouting quantity synchronously, and the stratum displacement in the construction process, etc. Based on the soil pressure balance shield tunneling construction in the east trunk canal of the South-to-North Water transfer Project in Beijing, this paper studies the residual soil improvement, the change law of the face pressure and the formation displacement during the construction process. The specific research contents and conclusions are as follows: 1 residual soil improvement experiment. A series of laboratory tests of residual soil improvement were designed, and soil improvement and optimization tests were carried out on fine sand and silty clay, respectively. The optimum foam injection ratio of fine sand is 8 and the best foam injection ratio of silty clay is 30. According to the volume difference of fine sand and silty clay, the optimum foam injection ratio parameter is calculated as 22.2 face pressure theory. By using different calculation theory of soil silo pressure, it is obtained that the pressure range of optimized back-up excavating face is 100-150KPa.3 monitoring of formation displacement. Surface displacement, vertical displacement of soil, horizontal displacement of soil and real time working parameters of shield machine were monitored. The vertical displacement of the stratum is divided into three stages, the uplift stage, the rapid subsidence stage, the slow settlement stage, and the horizontal displacement change in the tunnel direction is also divided into three stages. At last, the total thrust of shield machine, the pressure of earth chamber and the torque of cutter head are positively correlated, and the variation of shield parameters has obvious influence on the formation displacement. 4 numerical simulation of stratum displacement change. In this paper, FLAC3D software is used to simulate and calculate the ground displacement change during shield tunneling in actual monitoring section. The variation law of stratum displacement obtained by simulation is similar to that of actual displacement. The conclusion of this paper is of reference significance for practical engineering and can be used for reference in the construction of earth pressure balance shield machine in similar strata.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.43
本文编号：2265533
[Abstract]:With the rapid development of urban tunnel engineering in China, the earth pressure balance shield method has been widely used in the construction of soft ground tunnel with the advantages of fast construction speed, low labor intensity, small environmental impact and construction economy. And achieved good results in technology and economy. However, there are still some problems in the construction of earth pressure balance shield machine, such as the speed of shield machine, the thrust, the earth pressure in the cabin, the rotation speed of the cutter head, the relationship between the unearthed quantity and the rotating speed of the screw conveyor, the blocking of the cutter head and the unobstructed excavations. How to choose the value of soil pressure can keep the balance of face surface, control the grouting pressure and grouting quantity synchronously, and the stratum displacement in the construction process, etc. Based on the soil pressure balance shield tunneling construction in the east trunk canal of the South-to-North Water transfer Project in Beijing, this paper studies the residual soil improvement, the change law of the face pressure and the formation displacement during the construction process. The specific research contents and conclusions are as follows: 1 residual soil improvement experiment. A series of laboratory tests of residual soil improvement were designed, and soil improvement and optimization tests were carried out on fine sand and silty clay, respectively. The optimum foam injection ratio of fine sand is 8 and the best foam injection ratio of silty clay is 30. According to the volume difference of fine sand and silty clay, the optimum foam injection ratio parameter is calculated as 22.2 face pressure theory. By using different calculation theory of soil silo pressure, it is obtained that the pressure range of optimized back-up excavating face is 100-150KPa.3 monitoring of formation displacement. Surface displacement, vertical displacement of soil, horizontal displacement of soil and real time working parameters of shield machine were monitored. The vertical displacement of the stratum is divided into three stages, the uplift stage, the rapid subsidence stage, the slow settlement stage, and the horizontal displacement change in the tunnel direction is also divided into three stages. At last, the total thrust of shield machine, the pressure of earth chamber and the torque of cutter head are positively correlated, and the variation of shield parameters has obvious influence on the formation displacement. 4 numerical simulation of stratum displacement change. In this paper, FLAC3D software is used to simulate and calculate the ground displacement change during shield tunneling in actual monitoring section. The variation law of stratum displacement obtained by simulation is similar to that of actual displacement. The conclusion of this paper is of reference significance for practical engineering and can be used for reference in the construction of earth pressure balance shield machine in similar strata.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U455.43
【参考文献】
相关期刊论文 前1条
1 乐贵平,赵宏伟,周秀普,孟学文;穿越全断面砾石层的盾构施工[J];现代隧道技术;2001年05期
，本文编号：2265533
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