Qingdao Subway Tunnel Lining Design Optimization

Qingdao is a beautiful seaside city, rapid economic development, it can also bring the worsening traffic in Qingdao, and this is also eager to build subway to alleviate traffic pressure. The granite Qingdao special geological conditions, determine the subway experience is not readily available reference, there is no corresponding standard to follow. This requires that the premise of ensuring safety, use of Qingdao's own rock parameters, to find a scientific, rational parameters of tunnel lining, the construction of the follow-up Qingdao subway has great significance!Tunnel lining structure for saving the investment and improve management of construction and operation of the economic benefits of great practical significance of the project, which has been the focus of our concern and research. In recent years, ZHENG Ying-ren, Hu Wenqing, Zhang Liming, who began to strength reduction applied to the tunnel project, and proposed the concept of the safety factor of the tunnel, underground tunnel to evaluate the stability of surrounding rock. It also gives parameters of the tunnel lining provides a good way, through the safety factor on the tunnel support parameters suggest improvements.This article will focus on the existing norms of Qingdao metro tunnel design do not quite meet the problem, use clear water channel test section of Qingdao subway geological and design information, by Zheng Yingren Academy of strength reduction factor of safety calculation theory, for the following aspects of the study:(1) Support different types and under different stress release rate of the overall safety factor of rock.(2) The excavation of the thickness of the order and under different spray support key parts of the safety factor.(3) two different lining thickness and stress release rate Lining key parts of the safety factor.Innovation of the paper is to propose a design of Qingdao subway lining optimization methods, some important conclusions are the following. Lining design parameters for the post-optimization step to lay a solid theoretical foundation, clear research ideas.(1)the use of strength reduction finite element for solving different rock conditions supporting the overall safety factor, the analysis found: sprayed concrete and shotcrete support for the supporting role of obvious anchor in the process although support also played a a role, but support little effect, little effect on the stability of the structure, the proposed construction could be offset or partial lifting anchor, not only save cost, but also shorten the construction period.(2) stress release rate of the rock surrounding the safety factor has significant influence, and with the support rate of stress release prior to the improvement of the safety factor of surrounding rock is constantly decreasing, and the change in relatively clear. And accordingly determine a reasonable support time.(3) proposed by numerical simulation, 15cm ~ 20cm, as the tunnel secondary lining construction in Qingdao minimum reference thickness.