陇东黄土塬区超长桩承载特性的分析研究

Study on Bearing Characteristics of Super Long Pile in Loess Plateau of East Gansu

随着社会经济的高速发展,我国中西部地区工程建设迎来了新的发展高潮,大厚度湿陷性黄土地区超高层建筑和大型高速铁路桥梁不断涌现,超长桩基础在陇东黄土塬地区被广泛应用。但陇东黄土塬被称为天下第一塬,区域内黄土厚度达200m以上,由于黄土的工程性质本身具有特殊性,从而使桩的承载性能也不相同。因此,通过室内试验和数值模拟的方法,对陇东黄土塬区工程建设中,经常使用的超长桩的承载性能进行了研究。研究结果表明:(1)随着地基土的深度不断增加,超长摩擦桩的侧摩阻力会逐渐先增大后减小;(2)相对短桩而言,超长摩擦桩的压缩-沉降变形曲线没有明显的拐点,为缓变型曲线;(3)超长摩擦桩桩身压缩量在桩顶处最大,沿桩身近似呈线性递减;(4)随着荷载的增加,超长摩擦桩的沉降逐渐变大。

With the development of social economy,the engineering construction in central and Western China has ushered in a new development climax.Super high-rise buildings and large high-speed railway bridges are emerging in the thick collapsible loess area.Super long pile foundation is widely used in the Loess Plateau area of East Gansu.However,Longdong loess plateau is known as the first plateau in the world,and the thickness of loess in the region is more than 200 m.Due to the particularity of the engineering properties of loess,the bearing performance of piles is also different.Therefore,through the methods of indoor test and numerical simulation,this paper studies the bearing performance of super long piles often used in the engineering construction of Longdong loess plateau.The results show that:(1)with the increasing depth of foundation soil,the side friction resistance of super long friction pile will gradually increase first and then decrease.(2)Compared with short pile,the compression settlement deformation curve of super long friction pile has no obvious inflection point,which is a slow deformation curve.(3)The compression of super long friction pile is the largest at the pile top and decreases linearly along the pile body.(4)With the increase of load,the settlement of super long friction pile increases.