A Deformation Control Method of Tunnel Surrounding Rock Applied to Granite Alteration Zone Under Seepage Conditions

Abstract

A method for controlling the deformation of surrounding rock of a tunnel in a granite alteration zone under seepage conditions, comprising the following steps: ① setting a grouting conduit in the surrounding rock along the excavation surface of the tunnel and within a certain range outside the tunnel outline; Internally press the grouting material; ③ After the grouting material solidifies and hardens, block the cracks in the surrounding rock; ④ Set a monitoring cross-section in the middle of the proposed excavation section, and measure the surrounding rock stress, pore water pressure and displacement deformation at three key points. Monitoring parameters, obtaining the dynamic change curve of each monitoring parameter, and then fitting the relevant theoretical model of each monitoring parameter; ⑤Simulating the excavation process; ⑥Simulating the influence of curtain grouting advance support control method on the stability and safety factor of surrounding rock; ⑦Analyze the deformation diagram of the surrounding rock, the distribution diagram of the yield zone, and the cloud diagram of the maximum principal stress and the minimum principal stress of the hematite slab, and obtain the optimal design value of the thickness of the hematite slab that can control the deformation of this type of surrounding rock.

Description

technical field [0001] The invention relates to tunnel engineering, in particular to a method for controlling deformation of tunnel surrounding rock applied to a granite alteration zone under seepage conditions. Background technique [0002] Due to its special diagenetic process and evolution process, the rock mass in the granite alteration zone has special mechanical properties such as low strength, water swelling and strain softening. Insufficient understanding of the distribution laws and engineering characteristics of granite alteration zone rock mass often brings great difficulties to engineering design and construction. In actual tunnel engineering, the seepage of groundwater and the strain softening characteristics of surrounding rock materials are the most important factors affecting tunnel deformation. The body strength is low, and the montmorillonite in the montmorillonized altered rock has the characteristics of water absorption and swelling, which can loosen and...

AI Technical Summary

Problems solved by technology

In addition, the granite intruded into the alteration zone in the later period, affected by multiple tectonic actions and magma intrusion, the joints and fissures of the rock mass developed, the rock mass was broken, and the rock mass was mostly loose gravel breccia and silt soil, with extremely poor stability

At the same time, the rock mass in the alteration zone has the characteristics of high sand content and large void ratio. Under the action of high dynamic water pressure, it is very easy to see seepage damage phenomena such as piping and flowing soil, which will cause the overall instability of the excavation surface.

[0003] Under the existing seepage conditions, the tunnel construction in the granite alteration zone adopts a single control method for groundwater drainage. During the excavation process, the mechanical properties of the granite alteration zone are easy to deteriorate. The construction design often differs from the actual situation, and many changes are often required. Design of support scheme, affecting construction efficiency and increasing tunnel construction cost

Images