无水大粒径卵石层中盾构开挖地层变形规律分析

发布时间：2018-04-12 08:57

本文选题：盾构隧道 + 无水大粒径卵石地层　；参考：《现代隧道技术》2015年06期

【摘要】：卵石地层结构松散、胶结程度差、颗粒之间点对点传力、地层灵敏性高,开挖过程极易造成地层大变形,对于盾构隧道的施工极为不利。为了探明盾构隧道穿越这种地层的变形规律,文章以首例盾构全断面全程穿越无水大粒径卵石地层工程——北京地铁9号线03标段为背景,采用有限差分软件FLAC3D进行数值模型分析。通过与普通地层对比分析可知,盾构隧道在大粒径卵石地层中掘进引起的地表最大沉降值、沉降槽宽度、超前变形范围及沉降量、掌子面变形均较大。常规的施工措施无法满足大粒径卵石地层的需求,需要采取土体改良、增大盾构刀盘开口率、提高千斤顶推力、施工过程动态控制等特殊措施对地层变形进行控制。实际监测数据表明所采取的工程措施能有效降低地层变形量,确保施工安全。
[Abstract]:The structure of pebble stratum is loose, the degree of cementation is poor, the point to point transmission force between particles is very high, the stratum sensitivity is high, and the excavation process is easy to cause large deformation of stratum, which is extremely unfavorable to the construction of shield tunnel.In order to prove the deformation law of shield tunneling through this kind of stratum, this paper takes the first full section of shield tunneling through section 03 of Beijing Metro Line 9 as the background.The finite difference software FLAC3D is used to analyze the numerical model.By comparing with ordinary strata, it can be seen that the maximum settlement value, width of settlement slot, advance deformation range and settlement amount caused by shield tunneling in large grain-size pebble strata are all large.Conventional construction measures can not meet the needs of large grain-size pebble strata. Special measures such as soil improvement, increasing the opening rate of shield cutters, increasing Jack thrust, and dynamic control of construction process are needed to control the formation deformation.The actual monitoring data show that the engineering measures adopted can effectively reduce the formation deformation and ensure the construction safety.
【作者单位】：北京市市政四建设工程有限责任公司;北京交通大学城市地下工程教育部重点实验室;
【分类号】：U455.43

【共引文献】