Heterogeneous information phase space reconstruction and stability prediction of filling body–surrounding rock combination

Traditional research believes that the filling body can effectively control stress concentration while ignoring the problems of unknown stability and the complex and changeable stress distribution of the filling body–surrounding rock combination under high-stress conditions.Current monitoring data processing methods cannot fully consider the complexity of monitoring objects,the diversity of monitoring methods,and the dynamics of monitoring data.To solve this problem,this paper proposes a phase space reconstruction and stability prediction method to process heterogeneous information of backfill–surrounding rock combinations.The three-dimensional monitoring system of a large-area filling body–surrounding rock combination in Longshou Mine was constructed by using drilling stress,multipoint displacement meter,and inclinometer.Varied information,such as the stress and displacement of the filling body–surrounding rock combination,was continuously obtained.Combined with the average mutual information method and the false nearest neighbor point method,the phase space of the heterogeneous information of the filling body–surrounding rock combination was then constructed.In this paper,the distance between the phase point and its nearest point was used as the index evaluation distance to evaluate the stability of the filling body–surrounding rock combination.The evaluated distances(ED)revealed a high sensitivity to the stability of the filling body–surrounding rock combination.The new method was then applied to calculate the time series of historically ED for 12 measuring points located at Longshou Mine.The moments of mutation in these time series were at least 3 months ahead of the roadway return dates.In the ED prediction experiments,the autoregressive integrated moving average model showed a higher prediction accuracy than the deep learning models(long short-term memory and Transformer).Furthermore,the root-mean-square error distribution of the prediction results peaked at 0.26,thus outperforming the no-prediction method in 70%of the cases.

Lateral shear performance of sheathed post-and-beam wooden structures with small panels

Sheathed post-and-beam wooden structures are distinct from light-wood structures.They allow for using sheathing panels that are smaller(0.91 m×1.82 m)than standard-sized panels(1.22 m×2.44 m or 2.44 m×2.44 m).Evidence indicates that nail spacing and panel thickness determine the lateral capacity of the wood frame shear walls.To verify the lateral shear performance of wood frame shear walls with smaller panels,we subjected 13 shear walls,measuring 0.91 m in width and 2.925 m in height,to a low-cycle cyclic loading test with three kinds of nail spacing and three panel thicknesses.A nonlinear numerical simulation analysis of the wall was conducted using ABAQUS finite element(FE)software,where a custom nonlinear spring element was used to simulate the sheathing-frame connection.The results indicate that the hysteretic performance of the walls was mainly determined by the hysteretic performance of the sheathing-frame connection.When same nail specifications were adopted,the stiffness and bearing capacity of the walls were inversely related to the nail spacing and directly related to the panel thickness.The shear wall remained in the elastic stage when the drift was 1/250 rad and ductility coefficients were all greater than 2.5,which satisfied the deformation requirements of residential structures.Based on the test and FE analysis results,the shear strength of the post-and-beam wooden structures with sheathed walls was determined.