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| Analytical solution of lateral bearing capacity of rigid single piles based on modified shaft resisting moment |
| JIANG Jie1，2，3，FU Chenzhi1，2，3，CHAI Wencheng1，2，3，ZHANG Tan1，2，3，OU Xiaoduo1，2，3 |
| (1. College of Civil Engineering and Architecture，Guangxi University，Nanning，Guangxi 530004，China；2. Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education，Guangxi University，Nanning，Guangxi 530004，China；
3. Guangxi Key Laboratory of Disaster Prevention and Engineering Safety，Guangxi University，Nanning，
Guangxi 530004，China) |
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Abstract For considering the effect of the vertical friction on the lateral bearing capacity of rigid single piles more accurately，the relationship between the maximum compressive soil pressure around the passive side and the total soil resistance was established by presuming that the compressive soil pressure around passive side presents a cosine function distribution. The modified vertical friction coefficient of the pile-soil interface was obtained by inverse derivation of the simulations of compressive soil pressure and vertical friction resistance. On this basis，the analytical expression of the shaft resisting moment was derived. Assuming that both the ultimate soil resistance and the modulus of horizontal subgrade reaction increase linearly with depth and the modulus of the horizontal subgrade reaction decreases nonlinearly with the displacement at ground surface，the equilibrium equations of the horizontal force and the moment were derived under three stages：soil resistance without yielding，soil resistance with yielding only in a region above the rotation point，and soil resistance with yielding in regions both above and below the rotation point. For avoiding the complexity of the numerical iteration program，the analytical solution of the lateral bearing capacity was obtained by regarding the horizontal displacement(y0) at the ground surface as a known quantity and the depth of the rotation point(a) as a variable with consideration of displacement loading method. Compared with the results of finite element analysis，model test and field test，the correctness of the proposed method was verified. Based on the verified analytical solution，a parametric analysis was carried out to explore the influential factors(e.g. pile diameter，internal friction angle and height of lateral force) of the lateral bearing capacity，maximum bending moment and rotation point depth of rigid single pile. The results show that the cosine function can satisfactorily characterize the distribution of compressive soil pressure around the passive side，and the calculated shaft resisting moment from the modified vertical friction coefficient of the pile-soil interface is more realistic. Ignoring the effect of the shaft resisting moment will significantly underestimate the lateral bearing capacity of rigid single pile，and the degree of underestimation increases with the increase of pile diameter，internal friction angle and the height of lateral force.
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2022, Vol. 41 
