Design method of anti-crack k value for temperature crack control of tunnel floor lining concrete

Abstract

The invention provides a method for designing the K value of the temperature crack control of the tunnel floor lining concrete, comprising the following steps: Step 1. Collecting data for the design and calculation of the temperature crack control of the tunnel floor lining concrete; Step 2. Analyzing and determining the temperature control crack resistance target and Allowable value of anti-cracking safety factor [K]; Step 3. Design temperature control anti-cracking measures, including: Step 3-1. Analyze variables and draw up multiple temperature-controlled anti-cracking construction measures for lining concrete; Step 3-2. Using the formula to calculate the minimum anti-cracking safety factor K of the lining concrete construction period of each scheme min ; step 3‑3. at K min In the case of ≥ [K], the preferred measures are based on simple, practical and economical principles for construction application. This method can not only design the temperature control and anti-cracking scheme in the design stage, but also can be used to optimize and improve the construction temperature control measures in real time in the process of pouring construction according to the problems found and the changes in construction technology and conditions, so as to achieve the temperature control goal.

Description

technical field [0001] The invention belongs to the technical field of temperature control and anti-cracking of engineering structures, and in particular relates to a design method for controlling the anti-cracking K value (safety factor) of temperature cracks in lining concrete of a tunnel bottom plate. Background technique [0002] Cracks are one of the main diseases of concrete. According to the dominant cause of cracks, it can be divided into two categories: structural cracks caused by external loads and non-structural cracks caused by deformation changes. Deformation effects include temperature, drying shrinkage and wet expansion, and deformation of surrounding rock, among which 80% are temperature cracks. In recent years, with the rapid development of water conservancy and hydropower engineering construction, the scale and section size of underground hydraulic engineering have become larger and larger, and the environmental conditions such as geology have become more ...

AI Technical Summary

Problems solved by technology

In doing so, firstly, the temperature control standard for dam concrete cannot be applied to the thin-walled lining structure, and does not reflect the influence of differences in concrete strength, surrounding rock performance, lining thickness, and structural scale; secondly, the construction unit calculates the maximum temperature inside the lining concrete. Large, a large number of coefficient values ​​are highly artificial; the temperature difference between the two aspects may lead to a large distance between the formulated construction plans, and the target of temperature crack control cannot be effectively achieved

In particular, the analytical temperature stress is not calculated

[0007] Based on the above situation, at present, there are no clear requirements and technical standards for temperature control and crack resistance of lining concrete in underground engineering construction; there is no simple and high-precision design method, and the finite element method is time-consuming and expensive, and cannot be applied without concrete test results. The preliminary design stage and the rapid adjustment of the construction plan; the strong constraint method has a large error, and the temperature stress cannot be calculated; it is difficult to quickly and effectively achieve the temperature crack control target

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