Study on Bearing Capacity of Weaken Foundation by Field In-Situ Tests in Zhangjiajie-Huayuan Expressway

Abstract

Though there are lots of test and detection methods for bearing capacity of foundation, choosing test detection methods was chaotic in construction due to lack of systemic occupation standards. Because test methods and quoted standards were adopted wrongly in construction, construction quality problems and potential dangers in engineering for highway subgrade appeared frequently. Aimed on the soft soil foundation in Zhangjiajie-Huayuan Expressway, the Boussinesq elasticity solution was introduced to calculate bearing capacity of foundation corresponding to different embankment height. Furthermore, slab loading test method and light dynamic penetration method were adopted to verify weaken foundation in-situ tests in Zhangjiajie-Huayuan Expressway. The relation between number of dynamic penetration blows and bearing capacity from slab loading test was obtained by linear fitting and logarithmic fitting respectively. Linear fitting results showed that both of the methods had good correlation because the correlation coefficient R2 exceeded 0.961 and 0.873 respectively for light dynamic penetration and Dutch light dynamic penetration. The fitting formula may provide a fast and convenient method for dynamic penetration to determine depth of removing silt. Moreover it is important to insure subgrade construction quality.