Surrounding rock deformation warning method for full-section excavation of small-diameter tunnels

Abstract

The method for early warning of surrounding rock deformation in the full-section excavation of small-diameter tunnels according to the present invention has the following steps: step 1, preliminary geological survey, rock core sampling, finding out the position and direction of rock joint fissures; determining the parameters of surrounding rock through geotechnical tests, Classify the surrounding rocks and summarize them into a table; according to the geological survey results, determine the design of the multi-point displacement meter installation plan: Step 2, tunnel excavation and multi-point displacement meter installation: Step 3, mid-term geological survey: Step 4, multi-point displacement meter Installation time record: Step 5, determine the early warning value of surrounding rock deformation; Step 6, observe and record the data of multi-point displacement meters, and determine the remedial treatment of dangerous sections.

Description

technical field [0001] The invention relates to a surrounding rock deformation safety pre-warning construction technology in the technical field of water conservancy engineering, which is aimed at using the new Austrian method for full-section excavation to construct a tunnel under the condition of poor surrounding rock conditions. Background technique [0002] At present, when using the new Austrian method to excavate and construct tunnels, in order to ensure construction quality and construction safety, a common method is to use multi-point displacement meters to monitor the deformation of the rock mass around the excavation section. Because the construction method is simple to use and the cost is reasonable, it is widely used in the field of water conservancy engineering in our country. The traditional multi-point displacement meter monitoring surrounding rock deformation technology is a relatively static technology: first, in the drawing design process, the designer sele...

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Problems solved by technology

[0004] After searching the existing technical literature, it is found that the specification "Technical Specifications for Bolt Sprayed Concrete Support" (GB50086-2001) stipulates the allowable deformation of the surrounding rock in tunnel excavation, but this regulation is only for the measured value of the convergence measurement point, and the In the actual construction, the accuracy of the convergence measuring point is not high, and it is greatly limited by the measurement conditions, and the measured value is not as reliable as the multi-point displacement meter; the installation of the multi-point displacement meter is specified in the "Technical Specifications for Safety Monitoring of Earth-rock Dams" (SL551-2012) and monitoring technology have made detailed regulations, but there are no specific regulations on the installation time of multi-point displacement meters

The multi-point displacement gauge installed inside the tunnel will lag behind the excavation of the tunnel. During this period of time, the surrounding rock has undergone a large deformation, and the existing early warning technology for deformation of the surrounding rock cannot take into account the deformation that has occurred before the installation of the multi-point displacement gauge. The deformation of the surrounding rock, obviously, the missed deformation of this part will affect the judgment of the engineer, and ultimately affect the safety of tunnel construction

Moreover, the existing technology mainly relies on the experience of engineers to judge the danger, and there is no special safety early warning technology

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