Tunnel construction method for side span non-filling type long and narrow shallow-bottom karst cave section

Abstract

The invention discloses a tunnel construction method for a side span non-filling type long and narrow shallow-bottom karst cave section, and relates to the field of underground engineering. The invention aims to provide a construction method for the side span karst cave section of a tunnel under the specific geological condition of a non-filling type long and narrow shallow-bottom karst cave. According to the technical scheme, the tunnel construction method for the side span non-filling type long and narrow shallow-bottom karst cave section comprises the steps that a karst cave cavity in the lower portion of a tunnel excavation face is backfilled with cave slag, a karst cave opening is reinforced after danger is eliminated, a tunnel arch outside the karst cave cavity is subjected to advance support, tunnel excavation is conducted in a segmented circulating excavation mode, steel frames are erected along the tunnel arch and the whole section of a side wall, the tunnel arch and the sidewall are supported through anchor rods of a construction system, surrounding rock around the karst cave wall at the bottom of the tunnel is reinforced, a reinforced concrete slab at the bottom of thetunnel is constructed, a karst cave drainage pipe is constructed, the tunnel side karst cave is backfilled with concrete, and finally a tunnel secondary reinforced concrete lining and a road surface are constructed. The tunnel construction method is suitable for the design and construction of the side span non-filling type long and narrow shallow-bottom karst cave section.

Description

technical field [0001] The invention relates to the field of underground engineering, in particular to a method for building a tunnel in a limestone area with karst caves. Background technique [0002] When building tunnels in limestone areas, it is easy to encounter caves. According to whether there is filling in the cave, the cave can be divided into filling cave and non-filling cave. In unfilled caves, due to differences in the size of the cave and the relative positional relationship between the cave and the tunnel, the treatment methods for the caves are different. The relevant content in the "14.3 Karst" part of the first volume of civil engineering (JTG3370.1-2018) of "Code for Design of Highway Tunnels" is: [0003] 14.3.1 According to the positional relationship between karst and tunnels, comprehensive treatment measures such as spanning, strengthening karst caves, backfilling karst caves, diverting and intercepting karst water, removing or reinforcing fillings, s...

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Problems solved by technology

[0009] For unfilled narrow, long, shallow-bottomed karst caves, the above-mentioned "Code for Design of Highway Tunnels" did not give specific treatment measures

In addition, in the Q & A (JTG / TD70-2010) "14 Special Geological Design" chapter of "Detailed Rules for the Design of Highway Tunnels" involves several tunnel design methods for karst geological conditions, but these methods have specific applicable conditions and are not suitable for unfilled tunnels. Narrow and shallow-bottomed karst cave

Therefore, there is no tunnel construction method for the side-span non-filling type narrow and long shallow-bottom karst cave section in the prior art

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