Surrounding rock deformation early-warning construction method for small-diameter tunnel full-section excavation

Abstract

The invention discloses a surrounding rock deformation early-warning construction method for small-diameter tunnel full-section excavation. The surrounding rock deformation early-warning construction method for small-diameter tunnel full-section excavation comprises the following steps of (1) carrying out the earlier-stage geological survey and rock core sampling, finding out the position and the trend of a joint fissure of the terrane, determining parameters of surrounding rock through soil tests, classifying the surrounding rock and summarizing the types of the surrounding rock to form a list, and determining the design of the multipoint displacement meter installation scheme according to the results of the geological survey; (2) carrying out tunnel excavation and installation of multipoint displacement meters; (3) carrying out the middle-stage geological survey; (4) recording the installation time of the multipoint displacement meters; (5) determining a surrounding rock deformation early-warning value; (6) carrying out observation recording on data of the multipoint displacement meters, and determining remediation treatment measures of the dangerous section.

Description

Technical field [0001] The present invention involves a surrounding rock deformation safety early warning construction technology used in the field of water conservancy engineering technology in the case of poor surrounding conditions. Background technique [0002] At present, when using the new Olympic Dharma excavation construction tunnel, in order to ensure the quality of construction and ensure construction safety, the common method is to use multi -point displacement monitoring to monitor the deformation of the rock body around the excavation section.Because the construction method is simple and the cost is reasonable, it is widely used in my country's water conservancy engineering community.Traditional multi -point displacement monitoring surrounding rock deformation technology is a relatively static technology: first, during the design of the drawing, the designer selects the monitoring point according to the relevant geological survey data;After the tunnel is excavated, t...

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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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