类矩形盾构隧道管片施工期内力分布规律研究
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摘要
对于使用阶段的隧道管片结构,其受力特性通常可以简化为平面应变问题进行分析;而在施工阶段,由于隧道纵向荷载的差异,边界约束条件的不均匀,施工荷载的交叉影响以及盾构施工的时间空间性,导致施工阶段管片受力成为一个三维问题.本文以宁波软土地层大断面类矩形盾构隧道为背景,依据现场试验来探索类矩形盾构隧道衬砌结构在施工期受力、变形的规律.研究表明:施工阶段中衬砌弯矩、轴力整体呈上小下大、左右对称分布;脱出盾尾阶段为施工过程中的最不利工况,管片和螺栓的应力水平迅速提高,之后随推进距离增大逐渐趋于稳定,管片中柱接近纯受压构件.研究认为同步注浆和纵向、环向螺栓对管片应力变化影响均较大,建议加强对同步注浆工艺的控制,加强螺栓初期预紧力和后期复拧的管理.
The mechanical characteristics of lining structure at operation stage can usually be simplified to the plane-strain problem. During the construction process, the analysis of segment stress becomes a threedimensional problem due to the difference of the tunnel longitudinal load, uneven conditions of the boundary constraints, the cross-direction impact of the construction load and the time and spatial distributions of shield construction. Based on the project of large-section quasi-rectangular shield tunneling in Ningbo's soft stratum,the internal force distribution and deformation during construction period are monitored and analyzed. Study shows that the bending moment and the axial force distribution are close to the pre-analytical results, and the distribution is symmetrical. The upper internal force is smaller than that in the lower area. The stage of separating from the shield tail is the most unfavorable period in the construction process. The stress of the segments and bolts is increased rapidly. Afterwards, the stress tends to be stabilized as the advancing distance increases. The center column can be regarded as a pure compression member. Synchronous grout, longitudinal and circumferential bolts have a great influence on the stress of the segments. Both the control of synchronous grouting pressure and the bolts management on the preload in initial stage and re-tightening in the late stage are suggested to be strengthened.
The mechanical characteristics of lining structure at operation stage can usually be simplified to the plane-strain problem. During the construction process, the analysis of segment stress becomes a threedimensional problem due to the difference of the tunnel longitudinal load, uneven conditions of the boundary constraints, the cross-direction impact of the construction load and the time and spatial distributions of shield construction. Based on the project of large-section quasi-rectangular shield tunneling in Ningbo's soft stratum,the internal force distribution and deformation during construction period are monitored and analyzed. Study shows that the bending moment and the axial force distribution are close to the pre-analytical results, and the distribution is symmetrical. The upper internal force is smaller than that in the lower area. The stage of separating from the shield tail is the most unfavorable period in the construction process. The stress of the segments and bolts is increased rapidly. Afterwards, the stress tends to be stabilized as the advancing distance increases. The center column can be regarded as a pure compression member. Synchronous grout, longitudinal and circumferential bolts have a great influence on the stress of the segments. Both the control of synchronous grouting pressure and the bolts management on the preload in initial stage and re-tightening in the late stage are suggested to be strengthened.
引文
[1]张风祥,朱合华,傅德明.盾构隧道[M].北京:人民交通出版社, 2004.
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[10]朱瑶宏,朱雁飞,黄德中,等.类矩形盾构法隧道关键技术研究与应用[J].隧道建设, 2017, 37(9):1055-1062.
[11]朱瑶宏,朱雁飞,叶宇航,等.类矩形盾构隧道衬砌结构受力性能的足尺试验研究[J].现代隧道技术,2016,53(S1):108-117.
[12]]叶宇航,黄德中,李刚,等.类矩形盾构隧道衬砌结构极限承载力足尺试验研究[J].现代隧道技术,2016,53(S1):118-127.
[13]马险峰,黄俊,俞登华.类矩形盾构隧道施工管片受力特性数值模拟研究[J].现代隧道技术,2016,53(S1):164-169.
[14]王东方,张维熙,董子博,等.类矩形盾构隧道衬砌结构受力的现场试验研究[J].现代隧道技术, 2016, 53(6):174-181.
[15]叶俊能,周顺华,季昌,等.软土地区类矩形盾构隧道施工期变形规律[J].现代隧道技术,2016,53(S1):248-256.
[2]魏纲.盾构法隧道施工引起的土体变形预测[J].岩石力学与工程学报, 2009, 28(2):418-424.
[3]张厚美.盾构隧道的理论研究与施工实践[M].北京:中国建筑工业出版社, 2010.
[4]何川,封坤,方勇.盾构法修建地铁隧道的技术现状与展望[J].西南交通大学学报, 2015, 50(1):97-109.
[5]张志勇,李淑海.城市矩形隧道的应用与施工工艺的发展[J].施工技术, 2009, 38(S1):54-56.
[6]朱瑶宏,朱雁飞,黄德中,等.类矩形盾构法隧道技术的开发与应用[J].现代隧道技术, 2016, 53(S1):1-12.
[7]杨志豪,沈张勇,朱雁飞,等.类矩形盾构隧道设计方案研究[J].现代隧道技术, 2016, 53(S1):83-91.
[8]朱瑶宏,黄德中,朱雁飞,等.类矩形盾构法隧道施工关键技术探索[J].现代隧道技术,2016,53(S1):170-180.
[9]龙建兵,杨志豪,沈张勇.类矩形盾构工法在宁波轨道交通工程中的应用探讨[J].地下工程与隧道,2016(3):1-6.
[10]朱瑶宏,朱雁飞,黄德中,等.类矩形盾构法隧道关键技术研究与应用[J].隧道建设, 2017, 37(9):1055-1062.
[11]朱瑶宏,朱雁飞,叶宇航,等.类矩形盾构隧道衬砌结构受力性能的足尺试验研究[J].现代隧道技术,2016,53(S1):108-117.
[12]]叶宇航,黄德中,李刚,等.类矩形盾构隧道衬砌结构极限承载力足尺试验研究[J].现代隧道技术,2016,53(S1):118-127.
[13]马险峰,黄俊,俞登华.类矩形盾构隧道施工管片受力特性数值模拟研究[J].现代隧道技术,2016,53(S1):164-169.
[14]王东方,张维熙,董子博,等.类矩形盾构隧道衬砌结构受力的现场试验研究[J].现代隧道技术, 2016, 53(6):174-181.
[15]叶俊能,周顺华,季昌,等.软土地区类矩形盾构隧道施工期变形规律[J].现代隧道技术,2016,53(S1):248-256.