Back Analysis and Calculation of Dynamic Mechanical Parameters of Rock Mass with Measured Blasting Vibration Signals

Abstract

How to obtain dynamic parameters of rock masses quickly and precisely is a popular and difficult problem, which plays a very important part in engineering design or construction. Currently, the methods used to obtain these parameters are in situ testing method, empirical formula, and so on. However, these methods have some shortcomings, such as large investment and long construction period, which cannot obtain the dynamic parameters precisely and quickly in the engineering scale. In this study, a new method of estimating the rock parameters based on the measured field blasting vibration signals is proposed according to theory of elastic stress wave. In addition, an improved method for S-wave identification used in engineering scale was proposed and then the numerical simulation is given to verify the feasibility. Comparison of the numerical identification results and theoretical results clearly show that the improved method is available in S-wave identification with errors less than 2%. By identifying the arrival times of P and S waves, the propagation velocities of P and S waves are calculated and the parameters of rock mass can be obtained at last. Through analyzing the measured field blasting vibration signals in Fengning pumped-storage power station, the dynamic elastic modulus of rock mass inversed by vibration signals is about 2.2∼2.9 times of its static elastic modulus, while the inversed dynamic Poisson's ratio is 0.9∼0.975 times of the static.

Prediction and Analysis Method of Mine Blasting Quality Based on GA-BP Neural Network

“…e two important steps of quantification and regional segmentation were studied, and a blasting rock distribution model with strong applicability and high processing efficiency was established, and a software package for automatic determination of ore block degree was developed [13][14][15]. However, the above research has not solved the corresponding problems well, so this paper puts forward the following innovations: ① Combining genetic algorithm and BP algorithm, a computer image recognition algorithm based on GA-BP depth neural network is proposed.…”

Study on the Weakening Law and Classification of Rock Mass Damage under Blasting Conditions

“…Results from Haghnejad et al [20] also showed that the blasting damage factors D and GSI play important roles in slope damage. Yang et al [21] used the rock acoustic P-wave velocity as a supplemental element to estimate the disturbance factor D and compensate for the disturbance factor D in the H-B failure criterion. Yang et al [22] investigated the relationship between the disturbance factor D and the damage depth based on rock acoustic wave velocity test results after blasting and studied the detrimental effects on the mechanical properties of the rock.…”

Mathematical and Mechanical Analysis of the Effect of Detonator Location and Its Improvement in Bench Blasting

“…Blasting is generally the initial stage of rock breakage in mines, quarries, or geotechnical constructions, and its outcome plays a strong role in all downstream operations, such as loading, hauling, and crushing [1][2][3][4]. In practice, bench blasting is the most widely used operation pattern [5,6]. However, oversize boulders and rock toes that significantly affect the efficiency and cost of downstream operations often appear in the conventional bench blasting [7].…”