摘要
路桥并线路基修筑引起既有桥桩产生挠曲、侧向位移,严重时可能会造成重大坍塌事故的发生。结合工程现场试验,针对道路施工对邻近桥桩影响问题提出就地固化联合复合地基加固新方法,联合数值模型分析就地固化深度、固化土弹性模量和复合地基相关因素对邻近桩基的保护效果。研究结果表明:搅拌桩加固影响深度为1.5倍桩长左右,素混凝土桩施工会对被动桩在0.75倍桩长左右处产生最大水平位移。就地固化(2.0 m)+水泥搅拌桩法(1.8 m)可极大减小被动桩浅层水平位移,保护桥桩的安全。当固化土水泥掺量为5%~7%、水泥搅拌桩水泥掺量为12%~18%时,提高水泥掺量对减小被动桩水平位移有着明显的作用。同时,将普通褥垫层水泥搅拌桩替换为就地固化+水泥搅拌桩复合地基,桩身最大负弯矩减小近16.6%。
The construction of road and bridge foundations causes the deflection and lateral displacement of existing bridge piles,and in severe cases,it may lead to major collapse accidents.Based on on-site engineering experiments,a new method of in-situ solidification combined with composite foundation reinforcement for the impact of road construction on adjacent bridge piles was proposed,combined with the numerical model to analyse the effect of in-situ solidification depth,elastic modulus of solidified soil and other composite foundation related factors on the protection of adjacent pile foundations.The results show that the reinforcement depth of the mixing pile is about 1.5 times the pile length,and the construction of the plain concrete pile will produce the maximum horizontal displacement of the passive pile at about 0.75 times the pile length.The in-situ solidification(2.0 m)and cement mixing pile method(1.8 m)can greatly reduce the shallow horizontal displacement of passive piles and protect the safety of bridge piles.When the cement content of the solidified soil is between 5%-7%,and the cement content of the cement mixing pile is within the range of 12%-18%,increasing the cement content has a significant effect on reducing the horizontal displacement of the passive pile.At the same time,replacing the ordinary cushion layer cement mixing pile with in-situ solidification+cement mixing pile composite foundation reduces the maximum negative bending moment of the pile body by nearly 16.6%.
作者
丰土根
高文
张箭
和宇珑
FENG Tugen;GAO Wen;ZHANG Jian;HE Yulong(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210098,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2024年第2期715-729,共15页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(52178386,52378336)
中央高校基本科研业务费专项资金资助项目(B220202016)。
关键词
软基处理
工程试验
数值模拟
复合地基
就地固化
被动桩
soft foundation treatment
engineering experiment
numerical simulation
composite foundation
in-situ curing
passive pile
