THE INVARIANT REPRESENTATION OF SPINS WITH APPLICATIONS IN THE THEORY OF FINITE DEFORMATIONS

Based on the general solution given to a kind of linear tensor equations,the spin of a symmetric tensor is derived in an invariant form.The result is applied to find the spins of the left and the tight stretch tensors and the relation among different rotation rate tensors has been discussed.According to work conjugacy,the relations between Cauchy stress and the stresses conjugate to Hill's generalized strains are obtained.Particularly,the logarithmic strain,its time rate and the conjugate stress have been discussed in de- tail.These results are important in modeling the constitutive relations for finite deformations in continuum me- chanics.

Multifractal characteristics of spatiotemporal distribution of earthquakes in intraplate and interplate regions

This paper analyzes the multifractal characteristics of spatio-temporal distribution of generalized strain release of earthquakes （GSRE） occurred in the eastern and western Chinese mainland （as an instance of intraplate region）, Taiwan region and New Zealand （as an instance of interplate region）. The results show that the multifractal characteristics of GSRE are closely related to the geodynamic environment. For the temporal distribution of strong events, the clustering feature is more evident in the interplate regions than that in the intraplate regions, while for small and moderate events, this difference is ambiguous. For the spatial distribution of strong earthquakes, the clustering feature is usually clearer in the intraplate regions than that in the interplate regions, while for small and moderate events, the case is just opposite.

Numerical simulation study on the influence of the ground stress field on the stability of roadways

We adopt the concept of generalized plane strain to model a roadway in a stress field.This can avoid limitations caused by simplifying the stress analysis as plane strain.FLAC3D was used to investigate the maximum tensile stress and displacement of a roadway in a known stress field for angles,α,between the roadway axial direction and the maximum principal stress of 0°,30°,45°,60° and 90°.This theory was applied to the analysis of an engineering case.The results indicate that stress and displacement of the surrounding rock increase as the angle,α,increases.This provides some significant guidance for a reasonable layout of roadways in a known stress field.

Pore Water Pressure Buildup Under Cyclic Rotation of Principal Stress and Stability Evaluation of Seabed Deposit

The cyclic rotation of principal stress direction with a constant amplitude is the characteristics of cyclic stress in seabed deposit induced by travelling waves. Presented in the paper are the results obtained from tests simulating the cyclic stress characteristics, with emphasis laid on the buildup of pore water pressure in soil samples. Regression analysis of test data shows that the pore water pressure can be expressed as the function of the number of cycles of cyclic loading, or as the function of generalized shear strain. Using the results thus obtained, the possibility of failure of seabed deposit under cyclic loading induced by travelling waves can be evaluated. The comparison with the results of conventional cyclic torsional shear tests shows that neglect of the effect of the cyclic rotation of the principal stress direction will result in considerable over-estimation of the stability of seabed deposit.

SiZer for exploration of inhomogeneous structure in temporal distribution of earth-quakes

In this paper, the inhomogeneous structure of generalized seismic strain release time series (GSSRTS) of earth- quakes in East, West China and their subtectonic regions as Xinjiang, Qinghai-Xizang (Tibetan) Plateau, Northeast China, North China, South China and Taiwan have been analyzed by using the method of significant analysis on zero crossings of derivatives (SiZer). Results show that when index η for estimating GSSRTS is close to zero and bandwidth is large enough, GSSRTSs feature significant increasing in Xinjiang, Northeast China, South China and Taiwan tectonic regions and decreasing in Qinghai-Xizang (Tibetan Platean) and North China tectonic regions from January 1, 1970 to January 1, 2000. While with the dwindling of bandwidth GSSRTSs in all the above tec- tonic regions characterize clustering, that is to say, significant increasing and decreasing emerge alternatively. When η is large enough, GSSRTSs would have no significant statistical variation in most of above tectonic regions except Qinghai-Xizang (Tibetan Platean) and Taiwan where significant increasing or decreasing hold in several time intervals within limited bandwidths.