Along with rapid development of high-grade highway,mountainous expressways are emerging in large numbers at present while the spacing between up and down tunnels are often set to be small when selecting tunnel route because of various restrictive conditions.Besides,the engineering environment of portal section is often more complicated with the characteristics of low rock grade shallow covering soil,unsymmetrical loading and so on.The geomorphologic shape and engineering geological condition in Hangzhou district are very complicated while the lithologies and the lithofacies of rocks in mountain terrain are more complicated,making simulation study on this typical kind of construction significant.Relying on the portal section of ramps located at south of Hangzhou Zizhi tunnels,a kind of numerical simulation method suitable for Hangzhou's mountain tunnel with complicated conditions is proposed.The rationality of simulation method and construction technology is proved through comparing simulation results with actual monitoring data.%随着高等级公路建设的迅猛发展,山区高速公路如今也大量涌现,其选线时往往受各种条件限制,使得上、下行隧道间出现间距较小的情况;而洞口处的工程条件又往往更为复杂,有围岩等级低、覆土厚度浅及各层土层不等厚等特点.杭州地区工程地质条件及地貌形态十分复杂,其中山岭区岩性、岩相更是变化多样,对此种典型条件下的施工模拟研究更有意义.以杭州市紫之隧道南口匝道洞口段为依托,提出了适合杭州地区山岭隧道复杂条件下的施工模拟方法.将模拟结果与监测数据对比分析,证明了模拟方法以及施工工艺的合理性.
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