水泥搅拌桩法处理软土地基中桥头跳车现象的影响因素分析
Influence factor analysis of cement mixing pile method in treating vehicle bumping at bridge head in soft soil foundation
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摘要: 桥头跳车问题是软土地基公路建设中出现的质量通病,使柔性路基与刚性基础衔接合理是处理这一问题的核心。在总结国内外相关研究成果基础上,结合天津某道路工程在路桥连接段采用的水泥搅拌桩地基处理方案,应用ABAQUS软件进行了数值模拟,分析了处理范围、桩长变化率与差异桩长设计对消除跳车与二次跳车现象的影响。结果表明,水泥搅拌桩法对减缓桥头跳车现象较为有效;随处理范围增大,路桥衔接处差异沉降略有增大,但可缓解二次跳车现象;沿道路延伸方向桩长变化率增大,可在缓解桥头跳车现象的同时显著减轻二次跳车现象;水泥搅拌桩桩长的增加,将导致路基处理段与非处理段衔接处二次跳车现象的加剧。Abstract: Vehicle bumping at bridge head is a common quality problem in highway construction on soft soil foundation. Reasonable transition of flexible and rigid foundations is the core of solving this problem. On the basis of summarizing the relavent research results, the cement-mixing-pile-foundation treatment scheme adopted in the connection area of bridge and highway project in Tianjin is simulated by ABAQUS. The influences of treatment scope, gradient of pile length and variable pile length on eliminating the first and second vehicle bumpings are analyzed. The results show that cement mixing pile method is very effective in eliminating the vehicle bumping at bridge head. With the enlargement of the length of treatment scope, differential settlement also increases slightly, but the vehicle bumping at the section between the treated and untreated area can be alleviated. The increase of the pile length ratio in the highway extension direction will alleviate the vehicle bumping both at bridge head and in the section between treated and untreated areas. The increase of the length of cement mixing pile will aggravate the vehicle bumping at the section between the treated and untreated areas.