IN-SITU TEST STUDY ON BEARING BEHAVIOR OF ANTI-FLOATING MICROPILE IN WEATHERED ROCK SITE

Anti-floating micropile has the virtue of strong strata adaptability，flexible layout，economical construction， quick hole forming，environmental protection and machinery miniaturization． Based on the static load test of eight anti-floating micropiles，the vertical pull-out bearing properties of anti-floating micropile in Qingdao weathered rock site have been studied． The test results show that the Q － s curves of the testing piles are of slow change type， ultimate uplift capacity of pile length with 4. 2 ～ 5. 1 m are 1 700 kN under the ultimate load，which can meet the design demands; the unit average ultimate side friction of single pile is 0. 307 ～ 0. 425 MPa under the ultimate load; with other conditions being unchanged，the unit average ultimate side friction of anti-floating micropile reduces with the increase in pile diameter．