ABSTRACT

The deformation fracture of slope caused by earthquake is a complicated process. In this paper, three typical geomechanical modes are summarized and concluded, i.e. the outerinclining bedded landslide model, the high-steep block (layer) bedded slope collapse model and the weak base landslide model, which are representative for the deformation fracture and instability of slope in areas with high earthquake intensity. We have also designed a set of geomechanical modeling test equipment, and developed corresponding models and techniques under vibration so as to conduct the mechanism test of the three typical geomechanical models. Through the modeling reproduction test of the process of deformation fracture, its typical characteristics under vibration are shown. Formation conditions, relevant factors and evolvement principles of typical instability mechanism due to earthquake are presented to offer scientific and reliable test data and a basis for further research and analysis.

1 INTRODUCTION

Deformation fracture of slope caused by earthquake is a complicated evolvement process. Modelling test of the concept model formed by the evolvement mechanism should be undertaken, taking use of the measures of geomechanics modelling through some understanding acquired from the geological analysis of typical examples and the established modes. Target of verification should be achieved trough the reproduction test of deformation fracture of slope under vibration to reveal the typical phenomena and important evidence of deformation fracture under vibration as well as the formation conditions, relevant factors and evolvement principles of instability mechanism of typical earthquake, so as to offer scientific and reliable data and evidences to the research and analysis. Therefore, we have developed the typical modelling test of geomechanics mechanism under vibration for the formation and evolvement process of outer-inclining bedded landslide model, high-steep block (layer) bedded slope collapsing model, weak base landslide model.

2 Modelling Test on Outer-inclining Bedded Landslide Mechanism
2.1 Test Model

The outer-inclining layer slope model is based on the relatively long consequent slope structure, and is stacked with sandstone block of 5cm long, 5cm wide, 5cm thick, and with a rock formation dip angle of 10o-40o. The blocks are bonded by cohesive soil, with a gradient of 60o-70o (Fig. 1). The base is a 10o-40o slope made of barite powder. The rectangular protractor of the model shall be 45cm long, 38cm high and 40cm wide with a scale of 1:1000.

(Figure in full paper)

2.2 Analysis of Test Result

(1) Deformation fracture of mountain usually occurs at the inflection of the vibration movement trajectory, i.e. at the inflection point where the moving direction changes. We can learn that from the trajectory image and the deformation symptom, normally, when the moving direction of the vibration table changes from left to the right, gliding or kelyphitic deformation and fracture may occur due to its direction opposite to the inertia moving direction of the model, and the same with the free direction. Moreover, when the acceleration moving direction changes from up to down, block with low structural strength may be separated from the whole mountain, and gliding or kelyphitic deformation.

This content is only available via PDF.
You can access this article if you purchase or spend a download.