Research Of Stability And Technical Measure For Side Slope Of Soil Cut Of Highway In Cold Region

Usually, there are some failures existing in the subgrade side slope of accomplished advanced highway in our province because of climate conditions' influence, such as scouring on slope, collapse of superficial layer, and damage or slipping of protection engineering etc. These failures not only impair directly whole performance and environmental coordination of highway, but also increase considerably difficulty and cost of curing and maintenance in later stage. Limited to the conditions of region and economy development, like the other areas in our country, the relative researches in our province are generally deficient. Many problems are still exist, such as the insufficient protection techniques and regional typical protection model, and random selection of plant type and random determination of gradient of side slope of trench etc. This subject investigated and generalized main protection types and existing conditions of subgrade side slope of advanced highway in Heilongjiang province. By analyzing main performance forms and affecting factors of side slope failures, on the basis of systematic observation and indoor-outdoor tests, the researches of frozing and thawing collapse and scouring ultimate gradient of side slope of soil subgrade were carried out. At the same time, this subject put forward the action ways of affecting factors and pointed out that the key factor triggering frozing and thawing collapse was not gradient but shear strength within the usual gradient range of subgrade(1:1～1:2). within feasible range of gradient, decreasing gradient cannot prevent from frozing and thawing collapse. However, the analysis showed that the additional load of masonary on slope had the obvious influence on stability of side slope. Consequently, the mechanics model of checking computations for stability of frozing and thawing collapse was put forward, and would be used for quantitative analysis and judgement of those factors. In this subject, rainfall tensities of different natural devisions in our province were divided, scouring ultimate grade of side slope was analyzed by adopting mechanics method. The gradient of 1:1 was in the range of ultimate gradient and would be affected severely by rainfall scouring, therefore, this gradient should be avoided or the scouring protection design should be strengthened if the gradient is adopted. At last, this subject put forward recommended protection types and construction crafts.