基于总安全系数法的喷射混凝土支护承载能力的试验研究

Experimental Study of Bearing Capacity of Shotcrete Lining Based on Total Safety Factor Method

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中文摘要：为验证总安全系数法中喷层的荷载结构模型及其安全系数计算方法,研制大型隧道结构模型试验系统,采取结构试验的方法,开展毛洞、不同厚度喷层以及二次衬砌的加载破坏试验.通过围岩和细砂材料的三轴试验明确模型试验中各材料的物理与力学参数,模拟毛洞、不同厚度喷层以及二次衬砌的加载破坏全过程,依据破坏状态明确喷层与二次衬砌的设计承载能力,试验中监测围岩应力应变、喷层内外侧应变和喷层位移,结合监测结果分析喷层与二次衬砌在承载过程中的变形特征与受力特征,明晰喷层与二次衬砌的承载机制,并与总安全系数法理论计算结果进行对比分析.结果表明:1)在试验断面条件下喷层受力状态为小偏心受压,喷层与围岩之间的粘结能有效传递剪力,从而减少了喷层的弯矩,有利于充分发挥喷层的抗压强度,同厚度情况下喷层的设计承载力要高于二次衬砌;2)试验得到的厚度为 2 cm和 4 cm喷层的设计承载力比总安全系数法理论计算结果分别大 27.0%和22.9%,表明总安全系数法的喷层承载力计算模型是合理的,并具有合适的安全性.

外文摘要：Herein,a large-scale tunnel structural model experimental system is established.First,loaded damage tests are conducted on tunnels without support,supported by shotcrete of various thicknesses,and supported by secondary lining through structural tests to validate the feasibility of the load structure model of the shotcrete layer using the total safety factor method and its calculation method.The physico-mechanical parameters of each material in the model test are then clarified through triaxial tests of the surrounding rocks and fine sand materials.The entire loaded damage process of the tunnels without support,supported by shotcrete of various thicknesses,and supported by secondary lining,is simulated.The designed bearing capacity of the shotcrete and secondary linings is determined according to tunnel failure states.The stress and strain of the surrounding rocks,internal and external strain of the shotcrete layers,and displacement of the shotcrete layers are monitored.Finally,the deformation and stress characteristics of shotcrete and secondary linings are analyzed for determining the bearing capacity of these materials.Comparing the results with the calculated results using the total safety factor method shows the following:(1)The stress of the shotcrete layer exhibits a small eccentric compressive stress.The cohesion between the shotcrete lining and surrounding rock mass can transfer the shearing force in the rock mass,reducing the bending moment and greatly improving the compressive strength of the shotcrete lining.The designed bearing capacity of the shotcrete lining is higher than that of the secondary lining under the same thickness.(2)The designed bearing capacities of the shotcrete lining with thicknesses of 2 and 4 cm are 27.0%and 22.9%higher,respectively,than the theoretical calculation results by the total safety factor method,indicating the rationality of the calculation model of the bearing capacity of the shotcrete lining by the total safety factor method.

外文关键词：

tunnelsupport structure designshotcrete layermodel testtotal safety factor methoddestructive testbearing capacity

作者：

肖明清、徐晨、崔岚、盛谦、陈健、谢壁婷、吴鹏

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作者单位：

中铁第四勘察设计院集团有限公司,湖北武汉 430063

水下隧道技术国家地方联合工程研究中心,湖北武汉 430063

中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉 430071

中国科学院大学,北京 100049

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关键词：

隧道支护结构设计喷射混凝土支护模型试验总安全系数法破坏试验承载能力

基金：

中国铁建股份有限公司科研计划中铁第四勘察设计院集团有限公司科技项目国家自然科学基金面上项目中国科学院青年创新促进会项目

项目编号：

2021-B182021K038522791182023344

出版年：

2024

DOI：

10.3973/j.issn.2096-4498.2024.03.004

隧道建设(中英文)

中铁隧道集团有限公司洛阳科学技术研究所

隧道建设(中英文)

CSTPCD北大核心

影响因子：0.785

ISSN：2096-4498

年,卷(期)：2024.44(3)

参考文献量25