大直径泥水平衡盾构穿越上软下硬地层的施工技术研究

发布时间：2018-01-14 12:11

本文关键词：大直径泥水平衡盾构穿越上软下硬地层的施工技术研究　出处：《西南交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着我国交通建设的飞速发展,采用大直径泥水盾构施工的隧道越来越多,穿越的地层也越来越复杂,盾构在掘进过程中难免会遇到各种不同的地质条件,尤其是在泛珠三角地区的盾构隧道施工将穿越更多的上软下硬地层,逐渐成为隧道工程学科研究的热点和难点。这种地层,不仅增加了盾构的施工难度,易造成盾构偏离轴线、喷涌、开挖面失稳、结泥饼、刀盘刀具严重磨损、软硬交界面处刀具的崩裂和导致地面严重沉降,同时还延误施工工期,增加工程整治费用。鉴于目前的情形,对于大直径泥水平衡盾构穿越上软下硬地层的施工技术研究就显得尤为迫切和重要。本文依托狮子洋隧道工程实例,系统总结了FEM数值模拟、刀盘刀具配置、掘进参数选择、姿态控制技术等上软下硬地层综合施工技术,极大的丰富了盾构施工技术,对类似地层的施工有极强的借鉴和指导意义,推广应用前景十分广阔。成果如下： 1、根据不同施工工况FEM数值模拟结果的分析比较,形成以下结论：盾构的开挖施工使得上部土层产生沉降位移,而下部岩层扰动位移场较小,隧道底板附近岩层出现较小上浮,同时,盾构施工参数对最大沉降位移和最小上浮位移有影响。 2、大直径泥水盾构在上软下硬地层施工中,盾构刀盘采用面板式,刀盘开口率选30%左右；刀具配置采用：外圈为4-6把滚刀,中外圈为全新旋转刮刀,内圈为磨损量不超标的旋转刮刀的混合刀具配置型式,并随开挖面硬岩比例和强度来调整滚刀所占比例。若上软下硬地层较长时,应考虑在外圈同一轨迹线上布置一把滚刀和一把刮刀,且刮刀应稍高于滚刀。 3、大直径泥水盾构在上软下硬地层施工中,盾构的掘进参数设置：通常情况下,扭矩系数一般不小于10,扭矩不应大于最大扭矩的80%,不应过分强调掘进速度。在充分注意刀盘的结构强度和盾构设计的最大能力的前提下,采用降低刀盘转速,转速在1.1～1.2rpm之间；增大刀盘扭矩,扭矩的范围基本上分布在5000～11000kNm；降低掘进速度,掘进速度平均在10～12mm/min;推力控制在4000-5000t。 4、在上软下硬地层中,管片的姿态应适应于盾构姿态,姿态控制的重点是两者的相对位置关系。掘进时产生的姿态突变,采用分区油压差的方法进行纠偏；在管片产生内爆、偏离轴线过大的情况下,采用应力释放和改变千斤顶使用数量实现纠偏。纠偏时,纠偏半径必须大于偏移半径,应长距离缓慢纠偏。
[Abstract]:With the rapid development of traffic construction in China, more and more tunnels are used for large diameter slurry shield construction, through the strata is more and more complicated, the shield will inevitably encounter all kinds of geological conditions in the tunneling process, especially the construction of shield tunnel in the Pan Pearl River Delta region will pass through more soft and hard strata, gradually become tunnel engineering research hotspot. This formation, not only increases the difficulty of construction of the shield, causing the shield off axis, spewing, instability of excavation face, mud cakes, cutter tool wear, soft interface tool and cracking caused serious ground subsidence, but also delay the construction period, increase the project the renovation costs. In view of the present situation, the research on construction technology of soft and hard formation through large diameter slurry shield is particularly urgent and important.
On the basis of Shiziyang Tunnel engineering examples, summarizes the FEM numerical simulation, cutter configuration, tunneling parameters selection, comprehensive construction technology of hard strata attitude control technology of soft, greatly enriched the shield construction technology, has a strong reference and guidance significance for the construction of similar stratum, promotion has very broad application prospects the results are as follows:
1, according to the comparative analysis of numerical simulation results of different construction conditions of FEM, formed the following conclusions: the excavation of shield construction makes the upper layer and the lower strata settlement displacement, displacement field of small disturbance, the tunnel floor near the rock appears small go up, at the same time, the shield construction parameters on the maximum displacement and the minimum displacement of floating.
2, large diameter slurry shield in soft ground under the hard construction, using panel type cutter, cutter opening rate of 30% or so; the outer 4-6 configuration tool: the hob, foreign ring for the new rotating blade, an inner rotating scraper wear not exceed the standard of mixed configuration tool, and with the excavation the surface of hard rock and the ratio of strength to adjust the proportion of hob. If the soft hard stratum is longer, should be considered in the outer ring of the same track line layout of a hob and a scraper blade, and should be slightly higher than the hob.
3, large diameter slurry shield in soft ground under the hard construction, set shield tunnelling parameters: normally, the torque coefficient is generally not less than 10, the maximum torque of the torque should not be greater than 80%, should not be too much emphasis on driving speed. In the premise of full attention to the wheel structure strength and the maximum capacity of the shield design and by reducing the cutter speed, speed between 1.1 ~ 1.2rpm; increase the cutter torque, torque range is basically distributed in 5000 ~ 11000kNm; reduce the driving speed, driving speed at an average of 10 ~ 12mm/min; thrust control in 4000-5000t.
4, in hard formation of soft segment, the attitude should be adapted to shield attitude, attitude control is the focus of the relative location of the two. When the driving posture mutation, by partition of pressure difference deviation; in segment implosion, away from excessive axis, the stress release and change the quantity deviation. Jack used correction, correction radius must be larger than the offset radius, should slow long distance correction.

【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.43

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