Fundamental Study on Evaluating Rock Slope Stability by Vibration Measurements Using Remote Vibration Measuring System

Abstract

Abstract. The purpose of this study is to clarify the relationship between the mechanical stability of rock brock and its vibration characteristics so as to propose a new method of rock stability evaluation by measuring the vibration of rocks using remote vibration measuring system. Preventing rockfall damages to railway caused by earthquake and other reasons is becoming important, and thus early detection methods for unstable rock blocks are necessary. Therefore, a new method of safe and efficient rock stability evaluation using remote vibration measurement system is needed. In this study, we executed model experiments using concrete blocks bound to the concrete base unit under different adhesion conditions using Laser Doppler Velocimeter (LDV). Through these experiments, quantitative relation between the mechanical stability and the dominant frequency of rock block vibration was clarified. In addition, we executed a numerical analysis using FEM and the relationship was confirmed by the analysis. From the results of the experiment and the analysis, we investigated the relationship between the overturn safety factor, which is defined as the ratio of overturning moment to the maximum resistance moment of the block, and the dominant frequency of the rock vibration, and proposed a new method of rock stability evaluation using this relationship. We also executed a numerical analysis of the relation between the mechanical stability and the dominant frequency of rock block vibration under the influence of seismic ground motion. From the results, we have evaluated the mechanical stability of the rock under the influence of earthquakes by calculating the safety factor.

Experimental Hazardous Rock Block Stability Assessment Based on Vibration Feature Parameters

“…For a structural dynamic analysis, we use a damping spring to simulate the stiffness characteristics of the potential failure plane [26,27], assuming that the rock block is a rigid body, the slope is a fixed body, and the deformation of the potential failure plane is linear elastic deformation within the amplitude range. e hazardous rock mass can thus be regarded as a dynamic system, and the main vibration mode is a swing around a fixed base point [28]. e dynamic model is shown in Figure 2.…”

<b>Development of an Aerial Survey System and Numerical Analysis Modeling Software for Unstable Rock Blocks</b>

“…Table 2 shows the summary of those analytical results. The overturn safety ratio shown in Table 2 is defined by (3) [5].…”

“…To make the rockfall risk evaluation method using vibration measurements [2,3] easier and safer to use, the stability of the blocks of rock was evaluated by estimating their natural frequency by virtue of a remote noncontact vibration measurement system developed by the Railway Technical Research Institute [4]. Although the noncontact vibration measurement technique has already reached a practical stage [1], the stability evaluation method has only reached a stage where simple evaluation concepts have been proposed [1,5]. To improve the evaluation accuracy of stability, consideration of the scale and supporting conditions of the rock block are necessary.…”