Study On Construction Technology Of Pile Foundation In Area Of Karst

Karst landforms are widely distributed in our country; they play a vital influence on the construction of the building foundation in the karsts region. With the strongly promoting of the new round Development of the West Regions, Transportation construction grows rapidly in southwest karsts region. As a result, it is a necessary to study systematically the karsts pile's construction technology and come up with the reasonable and sophisticated design methods.The paper analyzes karsts cave under the piled foundation and overburden-karsts free face with a weak structural plane by mechanics, and studies on bridge piled foundation construction and quality accident on the basis of the field research and references to literature search. Specifically, has carried out following several researches:(1) The stress concentration of karsts cave under the piled foundation for two shapes of pile was calculated by elastic-plastic mechanics theory analysis, the impact on the stability of ground water level and shape of karsts cave to karsts cave under the piled foundation was also discussed.(2)The upper bound limit analysis have been analyzed to stability of the overburden-karsts free face with a weak structural plane, and established to the safety factor formula. As well as, it has been to investigate the influence of the free face stability that produce from the structural plane angle, the structural plane height, the overburden soil layer thickness and the pile load.(3)Through actual research in construction site, with the special geological conditions in karsts areas, for different karsts topography, proposed the principle and elements of the Pile Foundation, and analyzed that the selection of pile foundation construction. Moreover, problems during pile foundation construction in karsts region are analyzed, and the corresponding countermeasures are given.(4)State that the quality accidents probably produced of pile foundation in karsts areas for different kinds of bad geological appearance, and analyze its reasons. Furthermore, give rise to some corresponding preventive measures and effective treatments that are used for quality accident of pile foundation. The paper main innovation work is as follows:(1)According to elastic-plastic mechanics, proposed method with a thick ball which is used for calculate the karsts cave under the piled foundation.