Method for treating light section tunnel collapse

Abstract

The invention discloses a method for treating light section tunnel collapse, relates to the technical field of tunnel construction, aims to treat larger collapse in a light section tunnel soft-crackedsurrounding rock tunnel section, and provides a practical and effective pre-act support method with a simple technology, high operability and the low manufacturing cost. According to the technical scheme, the method for treating the light section tunnel collapse comprises the steps that by reinforcing loose slag bodies of collapse bodies in tunnel, above a springing line, a small pipe and a grouting body are integrated to form a shell to effectively support loose rock mass on the upper part; and collapse bodies under the springing line are pre-consolidated, in the process of slag draining, areserve core soil method is used for conducting excavation support, and then a collapse section is safely and quickly passed.According to the method, aiming at the light section tunnel soft-cracked surrounding rock tunnel section, the method is suitable for treating conditions of the larger collapse on the tunnel face and the top part and unable continuing slag draining, the technology is simple,the operability is high, the method is practical and effective, a construction process can be accelerated, and the safety risk of the construction is reduced.

Description

technical field [0001] The invention relates to the technical field of tunnel construction, in particular to a method suitable for processing landslides occurring in weak and broken surrounding rock tunnel sections of small-section tunnels. Background technique [0002] After a landslide accident occurs in the weak and broken surrounding rock section of a small-section tunnel, there are currently three common treatment methods: Method 1: Grouting and anchoring. This method is based on the "non-casing hole forming technology" and "medium-high pressure grouting" for the landslide treatment scheme of the grouting anchorage method. Method 2: Large pipe shed grouting advance support method, also known as small pilot tunnel method. This method mainly adopts a large grouting pipe shed supplemented by a small grouting conduit to pre-support the landslide body, and adopts short footage and staged excavation to support the landslide body as it is dug and supported. Method 3: single-...

AI Technical Summary

Problems solved by technology

[0003] The "non-casing hole forming technology" adopted by the grouting anchorage method is the key to the success of the scheme. In loose rock formations, especially in the collapsed body, it is easy to cause collapsed holes, which often leads to the failure of the scheme to be implemented smoothly.

Large pipe shed grout advance support adopts grouting large pipe shed supplemented by grouting small conduit, which is suitable for dealing with large section and large landslide tunnel section. The technology is relatively complicated and the cost is high

[0004] For loose and broken tunnel sections where the landslide body develops in a large range along the tunnel axis, the single-row advanced small conduit grouting pre-consolidation method has certain limitations: First, if the elevation angle of the advanced small conduit is small, the arching line The grouting consolidation thickness of the above collapse body is limited, and it is impossible to form a certain thickness of consolidation body to provide sufficient bearing capacity for the upper part; among them, the shallower the grouting consolidation depth, the smaller the thickness of the consolidation body

Second, if the elevation angle of the leading small conduit is large, although a consolidated body of sufficient thickness can be formed above the camber line, considering the operability of the construction, the large elevation angle in small-section tunnels will limit the drilling depth. Problems that may lead to inability to select the appropriate length of leading small catheter

At the same time, when the elevation angle of the leading small conduit is large, during the continuous advancement of the excavation of the landslide body, as the excavation depth increases, the greater the deviation between the small conduit and the designed hole excavation line on the top of the cave will increase the difficulty of excavation. And there is also the possibility of secondary collapse due to the lack of effective support of the consolidated body under the small duct

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