Regression Analysis And Fitting Of Initial Geo-stress Field In Hydraulic Engineering And Application In Project

Firstly, this paper makes a comprehensive summary and generalization to the fundamental distribution regularities of geo-stress field and the back analysis method to geo-stress at the present stage that is used at home and abroad .On the basic of systematically analyzing the research findings from predecessors, this paper makes improvements and supplements for their work, and thinks through the effects from the fault age and the rock material's property, and evolves a back analysis method to geo finally, which is more comprehensive. The particular jobs this paper has done are as follows:1. There are many ways of back analysis to initial geo-stress field at home and abroad now. whose modeling processes almost take no account of the fault age's effect or the specific properties of rock mass, for example, the transverse isotropy of some rock masses. This paper took the underground power house part of River Construction Shuangjiangkou for example, seriously considered the fault age in the mountain massif and the transverse isotropy of rock mass, which made the data calculation process more close to the real situation, and supplied the next stability calculation with more exactly geo-stress fields.2. Methods that analyze the inversion of geo-stress field are complicated at home and abroad, but there are two ways on the whole: one is inflicting load on border to simulate geologic movement, which has been used generally; the other is inflicting displacement on border to simulate, which is not prevalent. This paper choose the latter after comparing the advantages disadvantages of the two ways.3.It's inconvenience to use three-dimensional finite element to make a computational analysis to the three-dimensional and discrete initial geo-stress field. It needs to fit a stress function according to precision. This paper showed two ways of fitting stress function according to different precision.4.The first one is employing SPSS software to segmental units when the accuracy is not high, then fitting the stress function(quadratic function). The second one is employing orthogonal polynomial to deal with all the units except those near the border, and fitting the corresponding orthogonal polynomial(make subareas when necessary) combining the properties of geotechnical engineer. The formula is applied simply. It can reflect the effects on geo-stress field from depth of burial and the landform of mountain massif, and the precision meets the demands. The latter is a common description method to field functions at mathematics, which is under the preferable mathematic theoretical support. This way can be taken when the precision demand is high.