High speed railway collapsible loess tunnel foundation base configuration

Abstract

The invention discloses a high-speed railway collapsible loess tunnel foundation reinforcement structure, aiming to effectively remove foundation loess collapsibility and meet the requirements on the smoothness of line height by a high-speed railway. The reinforcement structures comprise an open cut section foundation base enforcement structure and a sub-surface excavation section foundation base enforcement structure, which both comprise cement-soil compaction piles (10) arranged in rows along the longitudinal and lateral directions of the foundation in a separating way, wherein, the lower ends of the cement-soil compaction piles (10) pass through the collapsible loess line and enter the old loess stratum. The invention has the beneficial effects of effectively removing foundation loess collapsibility, meeting the requirement on the smoothness of line height by the high-speed railway, and the tunnel initial-stage supporting structure of reinforcement process is safe, which has small influence on stability, tunnel initial-stage supporting surface has no obvious crack, arch crown sinking can be controlled within 1-2mm, level convergence can be controlled within 2-3mm.

Description

technical field [0001] The invention relates to a high-speed railway tunnel foundation, in particular to a high-speed railway collapsible loess tunnel foundation. Background technique [0002] Zhengzhou-Xi'an Railway Passenger Dedicated Line, with a total length of 458.8km, is the first railway passenger dedicated line newly built in the loess area in my country with an operating speed of 350km / h. There are a total of 38 tunnels along the line, with a total length of about 77km, of which the total length of the loess tunnel is 50km. The distribution of collapsible loess along the line is very complicated. The collapsible loess section accounts for 65% of the total length of the entire line, and the self-weight collapsible loess accounts for about 27% of the total length of the line. The degree of collapsibility ranges from slight (level I) to very severe Severe (level IV), distributed throughout the dedicated line section. The ballastless track is laid in the passenger ded...

AI Technical Summary

Problems solved by technology

These methods have been formed and widely used in geotechnical engineering outside of tunnels, but there is still a lack of examples of implementation in tunnels under primary support conditions, and of course there is no experience and technology in this regard

[0004] Based on the particularity of the Zhengzhou-Xi’an Railway Passenger Dedicated Line tunnel, that is, the surrounding rock is dry sandy loess with well-developed vertical joints, and the thickness of the self-weight collapsible loess at the bottom of the tunnel reaches 8-9m. The construction site is affected by the excavation of the tunnel face and cavern space, and the interaction and interference between section excavation-section stabilization-basement reinforcement-excavation surface support in time and space, the current calculation theory, processing method, construction machinery and construction technology are all It is difficult to meet the requirements, especially for the construction space and the vibration effect on the primary support / surrounding rock, and there is no experience for reference

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