An on-site measuring device and method for linear expansion coefficient of concrete dam

Abstract

The invention discloses an in situ measurement device for concrete dam coefficient of linear expansion and a measuring method thereof. The in situ measurement device for the concrete dam coefficient of linear expansion comprises a measuring device arranged in a concrete dam and an observation instrument connected with the measuring device. The measuring device comprises inner thermometers, outer thermometers, a strain gauge and two quartz glass tubes with different lengths coaxially connected with two ends of the strain gauge through a heat-shrinkable tubing correspondingly, foam filling materials overall coated on the periphery of the two quartz glass tubes, PVC protective casings and a thermal-protective coating, wherein the inner thermometers are attached to the surfaces of the two quartz glass tubes, the outer thermometers are arranged on the outer surface of the thermal-protective coating and are in contact with concrete, and outer end faces of the two quartz glass tubes are inserted into the concrete and are in contact with the concrete. The observation instrument comprises a temperature collecting module connected with the inner thermometers and the outer thermometers and a strain gauge sensor connected with the strain gauge. When temperature in the concrete dam changes, the concrete produces strain. The temperature and the corresponding strain of the concrete in the range of the measuring device are measured by the thermometers and the strain gauge in the measuring device. After adding the strain of the device, the coefficient of linear expansion of the concrete is calculated.

Description

technical field [0001] The invention relates to a concrete dam, in particular to a device and method for measuring the linear expansion coefficient of a concrete dam. Background technique [0002] In large-scale concrete structural projects such as hydraulic engineering and civil engineering, concrete temperature changes have a significant impact on structural displacement and stress, and the linear expansion coefficient is one of the key parameters affecting the calculation of concrete temperature and stress. Therefore, in order to meet the needs of concrete dam temperature stress calculation and the implementation of concrete dam temperature control scheme, a more accurate concrete linear expansion coefficient should be provided as much as possible. [0003] There are three commonly used methods for determining the linear expansion coefficient of concrete dams. One is to use the test value, that is, according to the design plan, make a concrete specimen close to the compo...

AI Technical Summary

Problems solved by technology

The limitation of this method is that the cost is high, and the size of the specimen cannot be too large. When there are large aggregates in the concrete on site, the test needs to remove the large aggregates, which will lead to significant differences between the test and the site conditions, and cannot reflect the random Influenced by various factors, the measured linear expansion coefficient is often quite different from the actual value

The second is to take the value based on experience. Since the internal and external conditions of each project are different, the empirical formula can only give a rough estimate at most.

The third is the inversion method based on the measured temperature data, which is commonly used as the inversion method of the measured value without stress. The volume is too small, and the large aggregate in the concrete dam needs to be removed, so the obtained result is quite different from the real value

Images