Study Of Creep Characteristic And Theory For Grouted Anchor In Red Clay

Red clay is widely distributed in Huguang region,Yunnan-Guizhou plateau,and the middle and lower reaches of the Yangtze River of China.When these areas are used for highway and railway construction,a large number of red clay slopes are bound to form.In many slope treatment technologies,anchor projects have been widely used because of their low cost,simple technology,quick construction,and reliable technology.The long-term stability of the anchorage project is an important criterion for judging the safety of the anchorage project,and the key to det ermine its long-term stability is the creep characteristics of the anchorage system,in which the water content and the grouting pressure of the soil around the anchorage project play a decisive role..In order to study the shear creep characteristics of the soil-anchor interface in the red clay layer,an in-house model test was conducted using a self-developed experimental device,and a soil-anchor interface shear creep test was performed for different water cuts and grouting pressures and conduct theoretical analysis.The main research contents of this article are as follows:(1)Conduct basic physical and mechanical characteristics tests on red clay taken from a high-speed road section in Ningxiang,Hunan.Make red clay layer anchor test specimens with different water content and grouting pressure and carry out soil-anchor interface shear creep test and soil-anchor interface transient shear test by using self-developed soil-anchor interface friction resistance performance sample preparation and testing device.The whole creep curve is obtained by step loading,and the creep curve of the stepwise loading is transformed into the creep curve respectively according to the "Chen’s loading method".Finally,the long-term strength of the anchor bar is obtained by the "isochronous curve method".(2)The traditional Burgers model often only has the fitting effect and neglects its prediction performance.The Newton component in the model is replaced with the component of the digital derivative software by introducing the fractional derivative,and the fractional derivative Burgers creep model is established.Use this model to fit and predict creep test results.(3)In order to obtain the component model with few parameters and high fitting precision,the software element based on fractional derivative is introduced into the traditional Merchant model.Establish the Merchant creep model based on fractional derivative,and the model was used to fit the creep curves under different water contents.(4)Selecting the shear creep test results under partial stress levels as learning samples,establish an adaptive fuzzy neural network model of the interface shear creep of red clay-anchored solids through the supervised learning of the samples,and the model pairs were predicted for the creep test results that were involved in the modeling.The model has reached certain accuracy in fitting and prediction,and has good generalization ability.