Postgrouting at the pile tip enhances the performance of cast-in-place piles.To clarify the performance of tip and side resistances,this study analyzed static load test data from two test piles before and after grouti...Postgrouting at the pile tip enhances the performance of cast-in-place piles.To clarify the performance of tip and side resistances,this study analyzed static load test data from two test piles before and after grouting.Mechanisms underlying an improvement in tip resistance and the influence of postgrouting on side resistance were investigated via theoretical analysis.Finally,a design method for tip resistance control via settlement was proposed.Results indicate that the ultimate bearing capacity of piles increases after grouting compared to before,underscoring the importance of tip grouting in gravelly soils and its profound impact on load transmission in pile foundations.Postgrouting at the pile tip enhances the strength as well as initial stiffness of the bearing stratum,ultimately elevating the overall pile foundation-bearing capacity.Additionally,tip grouting helps in strengthening over-all side resistance,especially around the pile tip.The grouting procedure has an impact on the soil’s arching effect at the pile tip;the extent of the arching effect and an increase in horizontal tension close to the pile tip are positively correlated with the effectiveness of grouting reinforcement.The design method for tip resistance control via settlement based on measured data statistics was validated using engineering examples,and the method has a practical reference value.展开更多
The application of pile-end post-grouting piles for super-large bridge pile foundations in some important projects was introduced in this paper.There are totally 21 test piles.The maximum pile diameter varies from 2.5...The application of pile-end post-grouting piles for super-large bridge pile foundations in some important projects was introduced in this paper.There are totally 21 test piles.The maximum pile diameter varies from 2.5 m to 3 m,and the maximum length is 125m;the bearing capacity of the post-grouting piles is over ten thousands tons.Based on the test results,the bearing capacity,displacement,and beating characteristics before and after grouting were analyzed.The results show that the beating capacity of the piles is increased in different degrees after grouting although the technical parameters,including the patterns of grouting pipes,pressure,dosages of cement,duration of grouting lasting time,are different.However,the obtained values are very discrete.In addition,the calculation formula for the post-grouting piles under specified grouting condition was deduced based on the statistics analysis results of 57 test piles.The research results have been applied in the design of bridge foundation.展开更多
基金The National Natural Science Foundation of China(No.52008100,52178317)the Natural Science Foundation of Jiangsu Province(No.BK20200400)+1 种基金China Postdoctoral Science Foundation(No.2022M723534)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(No.23KJA560005).
文摘Postgrouting at the pile tip enhances the performance of cast-in-place piles.To clarify the performance of tip and side resistances,this study analyzed static load test data from two test piles before and after grouting.Mechanisms underlying an improvement in tip resistance and the influence of postgrouting on side resistance were investigated via theoretical analysis.Finally,a design method for tip resistance control via settlement was proposed.Results indicate that the ultimate bearing capacity of piles increases after grouting compared to before,underscoring the importance of tip grouting in gravelly soils and its profound impact on load transmission in pile foundations.Postgrouting at the pile tip enhances the strength as well as initial stiffness of the bearing stratum,ultimately elevating the overall pile foundation-bearing capacity.Additionally,tip grouting helps in strengthening over-all side resistance,especially around the pile tip.The grouting procedure has an impact on the soil’s arching effect at the pile tip;the extent of the arching effect and an increase in horizontal tension close to the pile tip are positively correlated with the effectiveness of grouting reinforcement.The design method for tip resistance control via settlement based on measured data statistics was validated using engineering examples,and the method has a practical reference value.
基金The research was supported by China State Science and Technology Supporting Program(No.2006BAG04B01).
文摘The application of pile-end post-grouting piles for super-large bridge pile foundations in some important projects was introduced in this paper.There are totally 21 test piles.The maximum pile diameter varies from 2.5 m to 3 m,and the maximum length is 125m;the bearing capacity of the post-grouting piles is over ten thousands tons.Based on the test results,the bearing capacity,displacement,and beating characteristics before and after grouting were analyzed.The results show that the beating capacity of the piles is increased in different degrees after grouting although the technical parameters,including the patterns of grouting pipes,pressure,dosages of cement,duration of grouting lasting time,are different.However,the obtained values are very discrete.In addition,the calculation formula for the post-grouting piles under specified grouting condition was deduced based on the statistics analysis results of 57 test piles.The research results have been applied in the design of bridge foundation.
