（1 南京工业大学交通运输工程学院, 南京 210009； 2 南京水利科学研究院岩土工程研究所,  南京 210024；  3 厦门市建设局, 厦门  361003)

［摘要］在土岩溶组合地层的高层建筑设计中，由于地基土支承刚度不均匀，导致建筑物基础的承载力不足或不均匀沉降较大，常规设计方法无法保证建筑物安全。以典型工程为例，详细论述桩筏基础主动控制技术应用于该项目的设计计算过程，并通过有限元模型与现场监测数据验证其合理性与可靠性。该工程在黏土分布区采用桩侧和桩端后注浆摩擦桩，在基岩区域通过削弱基岩支承刚度，采用在桩顶设置刚度调节装置的桩（墩）基础，保证了黏土分布区支承刚度与基岩区支承刚度相匹配，满足承载力的同时有效地控制了基础的差异沉降。同时数值计算结果也表明，此工程基础设计方案是合理的，实测结果显示建筑物的不均匀沉降和总体沉降量均较小，验证了在桩顶设置刚度调节装置在土岩溶复杂地质条件下的适应性，取得了显著的经济效益。

［关键词］沉降控制； 刚度调节装置； 地基土支承刚度； 桩土共同作用； 变刚度调平； 复合地基

中图分类号：TU473-1文献标识码：A文章编号：1002-848X(2019)06-0116-06

Design of controllable stiffness pile-raft foundation in soil-Karst composite area

Zhou Feng1, Zhu Rui1, 2, Wang Xudong1, Lin Shuzhi3

(1 College of Transportation Science and Engineering, Nanjing Tech University, Nanjing 210009, China; 2 Geotechnical Engineering Department, Nanjing Hydraulic Research Institute, Nanjing 210024, China;3 Xiamen Construction and Administration Bureau, Xiamen 361003, China)

Abstract:In the design of high-rise building in soil-Karst composite area, the foundation soil bearing stiffness is not uniform, which often leads to weak bearing capacity or  larger uneven settlement. The conventional design method cannot guarantee the safety of buildings. A typical project was used as an example to describe the design and calculation process of the application of active control technology of pile raft foundation. The rationality and reliability of the application were verified through the field monitoring data and finite element analysis. This project used the friction pile with grouting technique of lateral and tip in the clay area. The supporting stiffness of the clay region was matched with the supporting stiffness of the bedrock area by weakening the support stiffness of the bedrock area and setting the stiffness adjustment device on the  top of pile by  pier foundation. All these effectively controlled the differential settlement of the foundation and satisfied the requirement of bearing capacity.Meanwhile numerical results show the rationality of the design scheme and the measured results show that the uneven settlement and the total settlement of the building are small, which verify that the stiffness adjustment device  on the top of  pile  is adaptable to the complex geological condition of Karst region and  remarkable economic benefit has been obtained.

Keywords:settlement control; stiffness adjustment device; supporting stiffness of foundation soil; pile-soil interaction; variable stiffness leveling; composite foundation

*国家自然科学基金面上项目（51778287）。

作者简介：朱锐，博士研究生，Email: yzzhurui@163.com。