Research On Monitoring Device Of Bolt Axial Force

The aim of this paper is to research the monitoring device of bolt axial force. Bolt anchoring technology is widely applied in mine roadway support, slope stability and the supporting system of deep excavation, geotechnical engineering, support of tunnels and caverns, dam foundation and bridge foundation, tower footing in China. Because of the bad work environment, the bolts always are eroded by groundwater which is rich in various minerals and disturbed by mining working in neighboring regions. These factors always break the bolts, and cause potentially hidden accidents in geotechnical engineering. But up to now, there is not a monitor which need not the system of energy supply, signal excitation, acceptance, transmission, processing, and the subsequent manual inspectiondo, do not damage the bolt anchoring quality, easy to install, and could provide effective long-term, low-cost and accurate monitor for the entire bolt supporting engineering, these enable the subject to become one of the challenging topics.This paper researches on piston bolt axial force monitoring device composed of adding carrier, carrying body, protective shield, pressure-sensitive chromogenic reagent, installed between bolt plate and bolt nut. According to the different states of the bolt axial force, there are color ranges marked in the protective shield and the color ranges correspond to the state of the axial force, the staff can be inferred by observing the color ranges on the device and get the bolt axial force. Firstly, this paper does theoretical research when tension acts on the bolt tip, and derives the distribution law of the bolt shear stress and axial force, and defines three different bolt stress state. Secondly, this paper studies and determines the materials of piston bolt axial force monitoring device composed of adding carrier, carrying body, protective shield, pressure-sensitive chromogenic reagent, and designs the structure of adding carrier, carrying body, protective shield, and determine basic dimensions of these three components, the chromogenic pressure of pressure-sensitive chromogenic reagent, the friction coefficient between the components which are mutual contact, tolerance of the important dimensions by nonlinear contact simulation analysis by ANSYS software. Finally, according to the results of the ANSYS, this paper marks the color ranges of pressure-sensitive chromogenic reagent on the contact surface of the protective shield of the piston bolt axial force monitoring device which correspond to the three different bolt stress state.Finally, this paper designs the piston bolt axial force monitoring device. The structure of device has been proved by ANSYS that is reasonable, and can reach the desired effect.