| Due to the characteristics of large vertical stiffness,strong bearing capacity,and good stability,the pile foundations are commonly found in the southeastern coastal cities that cover the extensive distribution of lacustrine,coastal,and lagoon-like soft soils.However,in addition to the vertical loads,the pile foundation should also have good horizontal bearing capacity,satisfying the requirements of the building to resist horizontal loads and overturning bending moments.However,till now,people still cannot fully understand the mechanism of pile-soil interaction under horizontal loading,and there is no unified effective calculation method to solve the displacement and internal force response of the pile under horizontal loading.In order to provide practical engineering with a high reference value,the paper relied on the full-scale model test of the Komengang Bridge to analyze various calculation methods through the horizontal static load test and pile-side loading test of a single pile.Adaptability.The main work and achievements are as follows:(1)A one-to-one test pile model was made on the original site,and the horizontal static load test and the pile side load test were completed.The test results show that the axial force of the test piles under the horizontal load is not large as a whole and can be neglected;the bending moment of the test piles is roughly "S",and the anti-bending point is near the silt layer and the granite layer.With the approach of the piled soil,the bending moment begins to increase,and due to the deeper impact of the silt layer on the piled soil,the pile body is subject to a wider distribution of lateral earth pressure along the depth,so pay attention to the silt layer.The effect of the heap on the adjacent piles.(2)The adaptability of the main calculation method of the active pile was studied.The results of the experiment were taken as references and the degree of coincidence of the calculation results was compared.The plastic method was simplified for the m method.The results show that the m method can describe the distribution of the pile deformation and the change trend with the increase of the horizontal load,but the accuracy is poor under large displacement.In addition,therecommended range of m in the coastal area of Fujian is 2?3MN/m4.In the case of small displacement,the p-y method has a large difference between the displacement calculation result and the actual measurement value,but the design result is safe;while in the case of large displacement,it is more superior than the m method but has poor operability.The N-L method is more simple,and its displacement results in both small and large displacements are well represented in terms of accuracy,but there is a large gap between the results of the moments and the measured values.Based on the simplified plasticity correction method proposed by the m method,the calculation process is simpler and easier to understand than the p-y method,and it also compensates for the poor accuracy of the m method in large displacement situations.(3)The adaptability of passive pile calculation method(soil displacement method and earth pressure method)was studied,and simplified cantilever pile method was proposed.The results are as follows.The calculation res-ults.of the soil displacement method are satisfactory,and the overall trend is in good agreement with the actual value.However,this method has high learning costs and the calculation process is complicated and difficult for engineers to accept.Simplified cantilever pile method still has defects that are difficult to avoid by the earth pressure method.The overall trend of the calculation results is not ideal;however,the calculation results at the control point of this method are gratifying,the error from the measured value is very small,and the accuracy is basically the same.Meet the requirements of practical application of the project,and the method is simple and easy to understand,calculation is fast,operability is strong,have high reference value and use value for engineers. |
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