Study On Design And Construction Technique Of Highway Tunnel In Loess

The paper analyses the stress characteristics of surrounding rock pressure, technology of draining off water, sectional form of lining, construction technology, disease treatment in the loess highway tunnel, based on a lot of built and building engineering, through field observation and numerical simulation and model test and spot investigation .By the observation in field of loess highway tunnel, researches the change regulations of the surrounding rock pressure acting on first lining and invert, axial force of lattice girder, contact stress between first and second lining and strain of second lining verse the time and distributions in different positions, summarizes the design principle of parameter in the loess highway tunnel: The structure design of lining should not according to surrounding rock classification, but should according to actual physics mechanics of surrounding rock; the surrounding rock pressure of deep soil tunnel can calculate by modified KAKE formula, the surrounding rock pressure of shallow soil tunnel belongs to flexible pressure and pressure figure seems cat ear; lateral pressure coefficient of loess tunnel is 0.6 ~ 1.0; second lining bears 15% of all loads.With the help of model tests and simulation analysis the influences of initial stress and forms of lining section on performances of lining were analyzed, and a ration form of lining sectional for loess highway tunnel was presented: lining sectional forms of single-center should be selected firstly; when the urgent parking is put up, the forms of three-center tabular circle is selected.The paper analyses the reasons of seeping out water, the forms of preventing and draining off water, the design program and the construction craft of preventing and draining off water through spot investigation. The type of welling up water is divided into four kinds: droping, pouring, emitting, giving off. The paper summarizes the design principle of preventing and draining off water in the loess highway tunnel, puts forward the forms of preventing and draining off water in the loess highway tunnel: preventing droping, preventing pouring, preventing emitting, analyses the application and construction of forms.The paper analyses the methods of excavation, the process and techniques of construction, the standards of quality assessment through relying on works. Summarizes the excavation technique of...