Experimental Study of Effects of Joint on Rock Fragmentation Mechanism by TBM Cutters

To study the effect of rock joint parameters, the joint orientation, the filling situation of joint and the distance between the center of joint and the position of penetration on rock fragmentation mechanism by tunnel boring machines (TBM) cutters, a series of penetration tests were conducted on rock-like specimens using the modified triaxial testing machine. Data of indentation load and penetration depth during the loading process were recorded and analyzed. Results show that the filling situation of joint can significantly influence the resistance of rock to penetration. The joint interface closer to the position of penetration plays a more positive role in rock fragmentation than that farther to the position of penetration. The joint orientation can greatly affect the peak indentation load, the anti-invasive factor, the crushing work as well as modes of rock fragmentation. With the increase of joint orientation, the peak indentation load, anti-invasive factor and crushing work decrease firstly, and then increase. When joint orientation equals to 60° and 90°, they reach the minimum and maximum values, respectively.

A New Design of Triaxial Test Chamber with Temperature and Pressure for Deep Rock

According to the research of existing triaxial testing machine of deep rock, a new test chamber with temperature-hold and pressure-tight is developed.The features of test box are as follows: a new kind of axial displacement test system with outer embedded type is designed for measuring the axial displacement of samples correctly; the circuit of oiling system is used to keep temperature and pressure; it’s convenient to take down the test box from the machine and the other functions of testing machine are not affected. So the availability factor of instrument can be improved. Finally, the thickness of cylinder wall is calculated, and according to the modeling and finite element analysis based on ANSYS, the results show that the cylinder can meet the working requirement.

An Information-Theoretic Approach for Computational Material Modeling

This paper presents an information-theoretic approach for computational material modeling, which characterizes materials by effectively utilizing all the known information including prior and empirical information. The approach is built within the framework of recursive Bayesian estimation where various inverse analysis techniques, such as Singular Value Decomposition (SVD) and Kalman Filter (KF) can be implemented. Numerical examples first investigate the validity of the proposed approach via parametric studies. The proposed approach has been then successfully applied to the identification of a composite specimen using a triaxial testing machine.