A tunnel bottom plate lining concrete temperature crack control anti-cracking K value design method

Abstract

The invention provides a tunnel bottom plate lining concrete temperature crack control anti-cracking K value design method. The method comprises the following steps of 1, collecting the data for tunnel bottom plate lining concrete temperature crack control design calculation; step 2, analyzing and determining a temperature control anti-cracking target and an anti-cracking safety coefficient allowable value K; step 3, designing a temperature control anti-cracking measure scheme, which comprises the following steps of step 3-1, analyzing a variable, and formulating a plurality of lining concretetemperature control anti-cracking construction measure schemes; step 3-2, calculating the minimum anti-cracking safety factor Kmin of each scheme in the lining concrete construction period by adopting a formula; and step 3-3, under the condition that Kmin is greater than or equal to K, optimally selecting a measure scheme for construction application according to a simple, practical and economicprinciple. According to the method, the temperature control anti-cracking scheme design can be carried out in the design stage, and the method can be used for optimizing and improving the constructiontemperature control measures in real time to achieve the temperature control target for finding problems and changing construction technologies, conditions and the like in the pouring construction process.

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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