In recent years,more and more large -span half-tunnel structures are adopted for highway tunnels.For such structures,there are many construction procedures,distribution of internal force of structures changes greatly,and indices during design and construction are difficult to control.For this purpose,this paper proposes half-tunnel structure safety coefficient method.Dependent on Jiangluo Road Shed-tunnel Project in Guangdong Province,the paper simulates the whole construction progress,and analyzes sectional safety coefficients of all parts in half-tunnel structures in combination with internal force of structures under all working conditions to determine the worst working conditions and distribution of safety coefficients of half-tunnel structures.The results of research show that except for large stress at intersection between baseplate structures and inclined columns of half -tunnel structures, safety coefficients of other parts are larger,and baseplate structures can be optimized;the stress on both ends of inclined columns is the maximal and is greatly affected by construction process;safety coefficients of canted walls and crown plate structures are higher,and structural sections can be further optimized.%近年来,公路隧道采用大跨半隧道结构逐渐增多.该类结构施工工序多,结构内力分布变化较大,设计和施工过程中难以把握控制指标.为此,提出半隧道结构安全系数分析法.以广东省江罗路棚洞工程为依托,模拟整个施工过程,并结合各工况下的结构内力,对半隧道结构各部件断面安全系数进行分析,以确定半隧道结构各构件的最不利工况及其安全系数分布.研究结果表明:半隧道结构底板结构除与斜柱相交处应力较大外,其余部位安全系数较大,且底板结构可进行优化处理;斜柱两端受力最大,且受施工过程的影响较大;曲墙及顶板结构安全系数较大,结构断面可进一步优化.
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