Karst tunnel bottom filling beaded type karst cave steel pipe pile grouting hole forming method

Abstract

The invention discloses a karst tunnel bottom filling beaded type karst cave steel pipe pile grouting hole forming method. The method comprises the following steps that firstly, tunnel bottom karst detection is conducted, specifically, tunnel bottom beaded type karst detection is conducted through a geological radar, for a section with determined karst, geological drilling is adopted for detectionconfirmation to determine beaded type karst distribution conditions including the number of karst caves, the sizes of the karst caves, the positions of the karst caves and karst cave filling conditions; and secondly, steel pipe pile grouting hole design is conducted, specifically, according to the beaded type karst distribution conditions, steel pipe pile grouting parameters are determined. According to the method, the hole forming problem of grouting reinforcement of karst tunnel filling beaded type karst cave steel pipe piles is well solved, through the arrangement of multiple stages of casing pipes, collapse of filler is effectively prevented, drilled holes can be relatively easily formed, drilling equipment is easy to machine on site, the cost is low, mounting and dismounting are easy, the construction speed is high, the hole forming rate is high, the construction period is greatly shortened, and the economic benefit and social benefit are obvious.

Description

technical field [0001] The invention relates to the technical field of foundation reinforcement drilling, in particular to a grouting method for filling beaded karst cave steel pipe piles at the bottom of karst tunnels. Background technique [0002] The stability of the surrounding rock at the bottom of the heavy-duty railway tunnel affects the later operation of the tunnel, and the vibration of the train load also affects the stability of the surrounding rock at the bottom of the tunnel. The Beishan No. 2 and Pengjialing tunnels built in karst areas are heavy-duty railway tunnels. Karst tunnels are developed at the bottom of karst tunnels, rock mass is broken, and multi-layered karst caves are superimposed. According to the later operation requirements, the surrounding rock at the bottom of the tunnel needs to be reinforced. [0003] Drilling technology is generally used in traditional steel pipe drilling, which is suitable for homogeneous and stable formations. However, ...

AI Technical Summary

Problems solved by technology

However, complex geological conditions make the construction of steel pipe columns more difficult, karst is developed at the bottom of the tunnel, and multi-layer karst caves are arranged alternately. Due to the filled karst caves, the filling materials are complex, including silt, gravel, etc., and the stability is poor. When the hole is disturbed, there are phenomena such as hole collapse, partial hole, and drill sticking, which make it difficult to pull out the drill bit. Even if the drill bit is pulled out, the drilled hole will become a waste hole and cannot be used again, resulting in a low hole formation rate and difficult hole formation at one time. It even needs to be drilled 2 to 3 times to meet the design requirements, the construction progress is slow, and the work efficiency is low. Therefore, it solves the problem of filling the beaded karst cave steel pipe pile grouting reinforcement drilling construction problem in the karst formation, and improves the drilling depth and hole formation rate. Key technology of pore formation in karst cave strata

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