Flexible pipe standard mark structure

Abstract

The invention discloses a flexible pipe standard mark structure which comprises a drilled hole and a steel protective pipe installed in the drilled hole. The hole bottom of the drilled hole is deeply inserted into bed rock, the steel protective pipe is fixed into the drilled hole through cement mortar, a flexible pipe is further installed in the steel protective pipe, the top end of the flexible pipe is fixedly connected with an outflow pipe at the bottom of a liquid box, a base is further fixedly connected with the bottom of the flexible pipe, and a liquid level sensor is arranged on the inner side of the base. The flexible pipe is installed in segment, flexible pipe segments are connected through sealing connectors, and corrugated pipes capable of freely stretching and retracting are arranged in the sealing connectors. The flexible pipe serves as a measuring pipe so that the structure can freely stretch and retract and can move in real time along with vertical displacement of the ground, and accordingly the absolute vertical displacement value is determined by measuring height changes of a vertical liquid column on the upper portion of the sensor. Besides, the structure is not affected by temperature and other external factors, and high measurement precision can be effectively guaranteed.

Description

technical field [0001] The invention belongs to the field of safety monitoring of hydropower and water conservancy projects, and in particular relates to a flexible pipe leveling structure. Background technique [0002] At present, the main technical means widely used in dam vertical displacement monitoring are: precision leveling method, static leveling method, vacuum laser alignment method and triangular elevation method. [0003] Usually, the vertical displacement measured on site is the displacement of a certain measuring point relative to the working base point, that is, the relative displacement. However, in order to obtain the absolute displacement of the measuring point, it is necessary to calibrate the displacement of the working base point itself. Checked by the benchmark point. Therefore, whether the benchmark point is stable will directly affect the accuracy of vertical displacement monitoring results. [0004] In order to ensure the stability of the benchmark ...

AI Technical Summary

Problems solved by technology

However, its use effect is not ideal in actual engineering, and there are mainly the following disadvantages: the bimetal standard has high requirements for buried installation, and the connection end of each steel pipe (aluminum pipe) must have sufficient rigidity and strength. Spacer rings should be used for support between the tube and the tube to prevent direct contact between the tube and the tube, and at the same time prevent the deflection of the tube in the hole. In addition, the diameter of the drilling hole required for the installation of the bimetallic standard is relatively large, making its cost more than other The monitoring method is much higher; the bimetal standard mainly uses the characteristic that the linear expansion coefficient of the steel pipe and the aluminum pipe is significantly different, which can eliminate the influence of temperature on the deformation of the pipe itself, so as to accurately determine the real vertical displacement value at the measuring point, but due to It is impossible for steel pipes and aluminum pipes to be homogeneous and isotropic, and their linear expansion coefficients are not constant, so there will still be a certain gap between the theoretically calculated value and the real situation. For example, the bimetallic standard used in the Three Gorges Project, if the theoretical line The expansion coefficient is used to calculate the vertical displacement. When the difference between the length of the steel pipe and the aluminum pipe reaches 3mm, the theoretical calculation result will deviate from the actual situation by more than 0.5mm, that is, the accuracy of the calculation result will not meet the requirements.

Images