Optimized neural network using beetle antennae search for predicting the unconfined compressive strength of jet grouting coalcretes

Abstract

Summary This investigation studied the coalcrete, a new supporting material produced by jet grouting (JG) for supporting surrounding coal seams. For support design, the unconfined compressive strength (UCS) of the coalcrete is an essential parameter to evaluate the jet grouting effect in coal mines. In this study, an intelligent technique was proposed for predicting the UCS of the coalcrete by combining back propagation neural network (BPNN) and beetle antennae search (BAS). The architecture of BPNN was first tuned by BAS, and then, the optimized BPNN‐BAS model was subsequently used for nonlinear relationship modeling. Several crucial influencing variables including water‐cement ratio, coal‐grout ratio, and curing time were selected as the inputs. By combining these variables, 360 coalcrete samples were prepared in a controlled laboratory environment and tested for establishing the dataset. The results demonstrate that BAS can tune the BPNN architecture more efficiently compared with random selection. Moreover, in comparison with multiple regression (MLR) and logistic regression (LR), and support vector machine (SVM), the optimized BPNN‐BAS model is more reliable and accurate for predicting coalcrete strength. Sensitivity analysis (SA) was used to obtain the variable importance, and the results demonstrate that curing time affects the UCS of the coalcrete most strongly, followed by water‐cement ratio and coal‐grout ratio. The success of this study provides an accurate and brief approach to coalcrete strength prediction.

Experimental and numerical investigation on a novel support system for controlling roadway deformation in underground coal mines

“…20 Considering the size effect of coalcrete, it is necessary to test the mechanical properties of that. 20 Considering the size effect of coalcrete, it is necessary to test the mechanical properties of that.…”

“…The function of coalcrete columns is to increase the shear strength of coal mass and form a stable support structure. 20 Considering the size effect of coalcrete, it is necessary to test the mechanical properties of that. A series of shear tests and compressive tests were performed.…”

“…The columns have a special performance with higher strength and lower deformability, which was called soilcrete or sandcrete. 20 Therefore, this can be seen as a presupport structure, which can be further enhanced by steel sets or rock bolts. Recently, the JG technique was tried in soft coal mass to form a stable "coalcrete" column in the underground coal roadway.…”

“…With the withdraw of drill stem, a coalcrete column was generated and finally more such columns created a stable coalcrete arch around roadway profile. 20 Therefore, this can be seen as a presupport structure, which can be further enhanced by steel sets or rock bolts.…”

Investigation on jet grouting support strategy for controlling time‐dependent deformation in the roadway

“…To overcome these limitations, a new grouting method for soft coal mass namely Jet Grouting (JG) was presented referring to JG treatment in geotechnical engineering . By the JG method, the high‐pressure cement grout was injected into soft coal mass and mixed with coal particles cut by high‐velocity jet and therefore a “coalcrete” composite with high strength was generated . Also, the model was verified.…”