Study on Influence of Clay Percent Moisture Content Change on the Working Mechanism of Micro Steel Pipe Piles

The paper deals with the model contrast test of micro steel pipe piles and with the study of change of their bearing capacity,deformation stress and failure mode under different conditions of soil properties by changing the percent moisture contents of the landslip soil.The test results show that the change of percent moisture content has great influence on the horizontal bearing capacity of the micro steel pipe piles: the percent moisture content increases,the bearing capacity of composite structure of the micro steel pipe pile decreases;the stress deformation of the micro pile varies with change of percent moisture content.When the percent moisture content is low,the micro pile suffers deformation in the slide bed and in the slide mass at the same time.When the percent moisture content is high,the deformation of the micro pile in the slide bed is more significant,and the change of negative bending moment value in the slide mass is slow.The soil pressure borne by the micro pile mostly concentrates on the vicinity of the slide plane.The certain area of the slide bed beneath the slide plane is considered the key part to resist slide of the micro piles.Within the certain limits of percent moisture content,high percent moisture content helps to create better bonding of micro piles and soil,to make all the rows of micro piles bear the loads evenly and to coordinate deformation.