Bearing Mechanism Of Punched Cast-in-situ Piles Of Karst Area

With the rapid development of China’s high-rise buildings, the application of pilefoundation is increasingly widespread. The punched cast-in-situ piles have the advantagesof a large punching diameter, a deep depth, a low construction cost, and an easy operation,and a large single pile capacity. The pile tip can reliably enter the bearing stratum, so thepunched cast-in-situ piles are widely used in the pile foundation of high-rise buildings.Because China’s karst areas are widely distributed, a large number of foundations areplaced on the top plate of karst. The karst areas have different geological conditions andmany impact factors. The load transfer mechanism of pile foundation of karst areas is notperfect, and there have been no realistic unified method of calculation. Therefore, thestudy on the bearing performance of pile foundation of karst area has importanttheoretical and practical values.In this paper, based on the domestic and foreign references and data, the strengththeory of rock mass structure is elaborated. Through the transfer analysis of piles’ sideresistance and tip resistance, the bearing mechanism of punched cast-in-situ piles of karstareas is studied in detail. The on-site test is conducted a project, and the finite differencesoftware FLAC is used to conduct the numerical simulation on the bearing stability ofpile foundation.Finally, through on-site tests, theoretical calculation and numerical simulationanalysis, the systematic study is made on the rock properties, load transfer mechanismand mechanical properties of karst cave roof and other aspects of punched cast-in-situpiles of karst area, and some important conclusions are drawn as the theoretical basis andtechnical guidance for the promotion and application of the technology in the actualprojects.