Research And Development Of Damage State Assessment System For Masonry Structure Under Blasting Vibration Effect

Masonry structure has a long history in China,which is the oldest and most widely used structural form.Blasting technology is widely used in engineering construction,and the disadvantage of the poor anti-vibration performance of masonry structure makes it easy to damage and high in failure rate under blasting construction.With the rapid development of computer technology and the mature application of various intelligent algorithms in various fields,computer software is gradually becoming an important tool to solve the scientific and technological problems in the field of engineering blasting.In this paper,the zoning method of blasting vibration,the prediction model of blasting vibration intensity and the safety criterion of masonry structure are studied.Based on the graphical user interface of MATLAB software,the damage state assessment system of blasting vibration effect of masonry structure is developed.The main achievements of this paper are as follows:(1)Based on the multi-resolution wavelet analysis of a large number of measured blasting vibration signals,the feature of energy proportion in each sub frequency band of the signal is extracted and studied,and a new blasting vibration zoning method based on energy proportion is proposed.Using the proposed zoning method of blasting vibration based on energy proportion,343 sets of measured blasting vibration signals are divided into different blasting vibration zones and the zoning results are used as samples to establish SVM classification models.The testing results demonstrate that the zoning method of blasting vibration based on energy proportion has high feasibility,flexibility and reliability,and the classification algorithm of SVM has high accuracy in blasting vibration zoning prediction.(2)A novel algorithm of Nested-ELM for predicting blasting vibration is proposed.Nested-ELM algorithm can quickly select the optimal input weights and biases of hidden nodes by setting MSE as the fitness function and combining with RBS method,and the algorithm can also quickly determine the optimal number of hidden nodes by setting its initial value according to the empirical formula and selecting MAPE as the diffusion search index.The feasibility and superiority of Nested-ELM algorithm for predicting blasting vibration are proved by the application of Nested-ELM model on four different types of blasting vibration samples.(3)The improved Anderson prediction model is loaded on the structural dynamic analysis model after amplitude modulation and frequency modulation,and the Newmark method is used for time history analysis.Combined with the vibration damage criteria for masonry structure,the safety criterion of“Frequency-Performance-Velocity” for masonry structure based on the improved Anderson model is proposed.(4)Based on the GUI platform of Matlab software,the intelligent visualization development of the damage state assessment system for masonry structure under blasting vibration effect is completed.The system consists of three main modules:“Blasting vibration zoning” module,“Blasting vibration intensity prediction” module and “Damage assessment of masonry structure” module.Besides,the main module“Damage assessment of masonry structure” includes three sub-modules,which are“Blasting vibration signal prediction” module,“Blasting vibration signal modulation”module and “Blasting vibration disaster prediction” module.This study can promote the further improvement of blasting vibration theory for masonry structure.Moreover,it has important theoretical significance for the safety evaluation,prediction and control of blasting vibration effect,and has a guiding role for the design and optimization of blasting engineering near buildings.