Study On Design And Calculation Of Shallow Buried Tunnels In Highway Engineering

There are mang heavy cuttings in highway engineering.If the choice is illogicality ,environmental disruption will arose ,bringing late stage tragic problems(such as landslide). Thispaper summarizes the problems of the heavy cutting projects. And the design philosophy ofenvironmental protection and sustainable development in the highway design is introduced.Heavy cutting project is compared with shallow buried tunnel project in engineering cost,long-lasting economic benefit, environmental protection. And this paper advises that shallowburied tunnel be used in the highway building. From heavy cutting is equal to shallow buried tunnel ,this paper gets the critical deepeningengineering cost hL as lower limit. Heavy cuttings are used when deepening is less than hL;Deep buried tunnel is used when deepening is more than hL. The wall rock pressure and lining internal force computing method of the shallow buriedtunnel is summarized. Assumed resisting power method of load-structure model is used tocalculate hemicycle lining under bias load.And this paper assumes that resisting power is accordwith parabola, gets all arch as basic configuration, gets formulation from the condition that therelative corner , horizontal displacement and vertical displacement of vault section iszero,adds deformation condition of maximum resisting power and zero resisting power, solvesequation group to get the internal force of lining . And lining internal force computing methodunder bias load based on assumed resisting power method is formulized.And this paper pointsout the key of this method is if the assumed regularities of distribution of wall rock resistingpower is correct.According to the deductive formulas programme is written to calculate theresisting power and internal force of the lining under symmetrical load and bias load.Theresisting power and internal force is symmetrical when the load is symmetrical which indicatesthat the formula is correct.This paper indicates that a simple effective method to apply theformula is to summarize the rule of the resisting power from the bias tunnel engineering.Finallynumerical method of load-structure model is used to study on the displacement and deformationof bend liner with the minishing wall rock resisting power modulus,and a ameliorated liner isgiven when the wall rock resisting power modulus is small.