盾构隧道过大变形微扰动注浆处理的流固耦合数值模拟

Yanjie Zhang^a, Zheng Cao^b, Chun Liu^b,*, Hongwei Huang^c,d

^a College of Civil Engineering and Architecture, Henan University of Technology, Zhengzhou 450001,

Henan, China

^b School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China

^c Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China

^d Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai

200092, China

Abstract: Micro-disturbance grouting is a recovery technique to reduce the excessive deformation of operational shield tunnels in urban areas. The grout mass behaves as a fluid in the ground before hardening to form a grout-soil mixture, which highlights the necessity of using fluidsolid coupling method in the simulation of grouting process. Within a discrete element modeling environment, this paper proposes a novel fluid-solid coupling method based on the pore density flow calculation. To demonstrate the effectiveness of this method, it is applied to numerical simulation of micro-disturbance grouting process for treatment of large transverse deformation of a shield tunnel in Shanghai Metro, China. The simulation results reveal the mechanism of recovering tunnel convergence by micro-disturbance grouting in terms of compaction and fracture of soil, energy analysis during grouting, and mechanical response of soil-tunnel interaction system. Furthermore, the influence of the three main grouting parameters (i.e., grouting pressure, grouting distance, and grouting height) on tunnel deformation recovery efficiency is evaluated through parametric analysis. In order to efficiently recover large transverse deformation of shield tunnel in Shanghai Metro, it is suggested that the grouting pressure should be about 0.55 MPa, the grouting height should be in the range of 6.2–7.0 m, and the grouting distance should be in the range of 3.0–3.6 m. The results provide a valuable reference for grouting treatment projects of over-deformed shield tunnel in soft soil areas.

Keywords: Fluid-solid coupling; Discrete element method; Pore density flow; Microdisturbance grouting; Soil-tunnel interaction

Fig. 2. Schematic diagram of pore density flow calculation system. (a) Discrete element accumulation, (b) pore fluid grid network, and (c) particle-pore system.

Fig.4. Flow chart of pore density flow calculation method.

Fig. 5. Soil-tunnel system and the grouting area. (a) Soil stratum model and particle diameter distribution, (b) location of shield tunnel in soil stratum, (c) deformation of shield tunnel under surcharge load, and (d) micro-disturbance grouting on both sides of the tunnel.

Fig. 6. Comparison between field measurement data and numerical simulation results on tunnel transverse convergence before grouting, convergence after grouting, recovered convergence, and recovery ratio by grouting.

Fig. 8. Development of soil fractures with increasing grout volume (the zones enveloped by red dashed lines denote soil fractures). (a) V=0.25 m3, (b) V=0.50 m3, (c) V=0.75 m3, and (d) V=1 m3

Fig. 9. Kinetic energy and heat through the grouting process. (a) Changes in kinetic energy and heat during the grouting process, and (b) heat distribution when grouting is completed.

Fig. 10. Distribution of soil stress field before and after grouting. (a) Horizontal stress before grouting, (b) horizontal stress after grouting, (c) vertical stress before grouting, and (d) vertical stress after grouting.

Zhang Y, Cao Z, Liu C, et al. Fluid-solid coupling numerical simulation of micro-disturbance grouting treatment for excessive deformation of shield tunnel[J]. Underground Space, 2024.

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