Study On Stability Mechanism For Half Filling And Half Digging Roadbed Slope

The cut and fill sub-grade , whose stability decided by the type of cut and fill interface and the physical and mechanical properties of interface ,is a common building model in the construction of highway in mountain area . In allusion to this problem, First, based on interface structure characteristic, The cut and fill sub-grades slope is divided into two kinds in stair level, high-steep interface sub-grades slope and common interface sub-grades slope.In succession, based on lithology, the slope is divided into three kinds in second level such as rocky interface sub-grades slope,soil interface sub-grades slope and soil-rock admixture interface sub-grades slope, Thus classify system of cut and fill sub-grades slope in mountain area construction site has been established. On the basis of the engineering types of slope, the engineering geological models and the relative failure mechanism of cut and fill sub-grades slope are investigated and concluded. Secondly, synthesis measure of selecting geotechnical mechanics parameter considering interface structure characteristic is put forword, and examinational date is deal with by random-fuzzy method. The selecting method and physics signification of weighting of fuzziness degree in the Random-fuzzy Calculate expression is discussed, the weightiness is considered as a variable, and the relative function expression is put forword. Consequently, the non-precise demerit of reasoning in the invariable weightiness random-fuzzy method is getted over, and the affect of result by using presume in the process of deducing formulary is eliminated. wjiBy the way of example relied on engineering , it is indicated that the variable weightiness random-fuzzy method is better than the classical stochastic method and invariable weightiness random-fuzzy method because its variance is less than the results obtained by stochastic method and invariable weightiness random-fuzzy method in any case. The results also indicate that the variable random-fuzzy statistic method is worth of being generalized in engineering application. The tests of single index and multiple factors were designed according to orthogonality table. high-steep interface sub-grades slope and common interface sub-grades slope are separately divided into three types, whose sensibilities of the factors influencing on the stability of slope were analyzed by use of the method of Sarma, and sensitive sequence of each type is present. the influence disciplinarian of the mechanics parameters of interface (cohesion,angle of internal friction) and geometry parameters (the obliqulity of filling,the width of filling rode surface,the gradient of sub-grades) to the stability coefficient of the cutting and filling sub-grades slope is put forword. Finally, the stability of the cutting and filling sub-grades of six typical segments for Xupu connection line of Shao Huai expressway is analyzed in the choosing stuffing,selecting the width of filling rode surface and Reinforcing, and the abecedarian advice which provide available reference to this project is brought forward.