Analysis Of Heterotaxis Based On Stochastic Media Theory And Research On Control Technology For Shallow Excavation Method

In this paper we combining connecting tunnel project of Subway Line 4 at Xidan-lingjing bystreet in Beijing. To aim at the difficulties of building large-span connecting tunnels in the fine sand layer, through roads and underground pipelines, construction nearby buildings and other project difficulties. Using theoretical analysis, numerical simulation, field tests and other research methods to comprehensive and systemic research the stratum deformation mechanism and process control techniques of shallow excavation method, and a series of results were obtained.Firstly, use the stochastic media theory to analyze the stratum deformation mechanism, concretely analyze the analytic equation of surface horizontal displacement and deformation which were caused by the excavation of single-hole and double-hole tunnel, and further discussion on ground settlement, vertical deformation, surface horizontal displacement and horizontal deformation. Analyzing the main influence factors of surface displacement, and combined with practical work to proof the theory which was applied to shallow buried single-hole tunnel in fine sand layer was scientific.Secondly, based on in situ monitoring analysis, summarized some change law of ground settlement, horizontal displacement and layered settlement in the fine sand layer.Thirdly, used numerical simulation to analyzed axial force variations of the two-layered ductules , and combined with monitor data, analyzed and concluded the mechanism of two-layered ductules. We also proofed the practicality of ground consolidation of the two-layered ductules in complicated formation condition and difficult construction environment through the research of two-layered ductules in construction application and field monitoring.Fourthly, to forecast the scale of ground settlement and layered settlement at different construction sequence and confirm the pre-grouting pipe-shed and small duct reinforcement through using numerical simulation to analyzed different reinforcement for the stratum of tri-arch tunnel. Proofed the reliability of numerical simulation by comparative analysis for ground settlement and layered settlement of the multi-pilot-cavity excavation.