Study On Creep Characteristics Of Anchors Under Intermittent Vibration Disturbance

As a very important support method,anchoring is widely used in geotechnical engineering such as tunnels,slopes and underground chambers.The creep of anchor is not only related to the long-term stability and safety of the project,but also the hotspot of current scholars.At present,the research on creep of anchors mostly focuses on the study under static load conditions,while the creep characteristics of anchors are less studied under vibration disturbance conditions.Therefore,it is of great practical significance to study the creep properties of anchors under intermittent vibration disturbance conditions.This article takes anchor as the research object,and the indoor model test method is used to apply the disturbance load to the anchor at different time intervals.The creep characteristics of anchorage under intermittent vibration disturbance are investigated by systematically analyzing strains in parallel and vertical loading directions.Firstly,a set of vibration disturbance anchorage engineering creep test system based on reaction frame was designed.A set of test devices is assembled by using the principle,and then an anchor sample is prepared by using cement mortar geotechnical similar materials;A vibrating box is preset in the anchor to simulate a vibrating disturbance environment.A vibrating box is embedded and a disturbance is applied at intervals of 20 minutes to simulate a low frequency vibration disturbance environment.Two vibrating boxes are embedded,and a disturbance is applied at intervals of 5 minutes to simulate a high-frequency vibration disturbing environment.The strain data around the anchor under the disturbance effect is obtained by pasting the strain gauges in the vertical and horizontal loading directions around the anchor sample.Secondly,the speckle processing is performed on the side of the sample portion.the relevant image is acquired by the camera,and the feature picture is analyzed by using MATLAB.Finally,by analyzing the strain changes of the anchor under low frequency vibration disturbance and high frequency vibration disturbance,the creep characteristics of the anchor under intermittent vibration disturbance conditions are obtained.The results show that under the low-frequency vibration disturbance,the anchor creep in the vertical loading direction of the anchor can be roughly divided into a slow growth phase,a constant velocity growth phase,and a stabilization phase.However,during the test,it is found that when the disturbance load is applied,the strain of the anchor will increase instantaneously,and the original creep rate will be restored when the disturbance load disappears.The horizontal direction shows the characteristics of large fluctuations;Under the high-frequency vibration disturbance,the creep rate of the anchor will increase significantly,which is roughly divided into creep growth,constant velocity growth,and accelerated growth.The research results can provide a reference for analyzing the long-term stability of anchoring engineering and studying the creep properties of anchors.