Abstract：In this paper，a novel technology of the vertical steel floral tube micropiles with twice grouting was proposed，and，based on large-scale model tank tests，the slope soil pressure，horizontal bearing capacity and flexural performance of the micropile were investigated in cases of no pile，a single pile with traditional one grouting，a single pile with twice grouting and three piles with twice grouting. The experimental results show that the fracturing pressure of the twice grouting is directly related to the interval time between the first grouting and the secondary grouting. The longer the interval time，the greater the fracturing pressure is. Compared with traditional one grouting，the horizontal bearing capacity of the twice grouting floral tube micropile increases by 24.42%. Compared with the 3-fold value of the horizontal sliding resistance，the horizontal bearing capacity of the structure with three micropiles is 20.25% higher. The force bearing point of the micropile against the landslide thrust moves down due to twice grouting，which improves the action mode of the landslide thrust. Test results show that the ultimate bending moment and bending resistance capacity of a single pile respectively increase by 12.8 kN•m and 96.2% with twice grouting. The technology significantly improves the horizontal bearing capacity of the steel floral tube micropile，enhances the soil reinforcement performance between piles and increases the shear capacity and flexural capacity of the micropile compared with the original technology.
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2019, Vol. 38 
