桩基础是目前国内外基础工程中应用最广泛、发展最迅速的一种基础形式,它的作用是把结构物承受的垂直和水平荷载以及弯矩传递到下部和周围的地基上。在国外,进入七十年代后,由于海底石油的开采,大型港口和深水码头的兴建和扩建,大型公路、铁路桥梁的建造,对桩基的发展提出了新的课题,即向大型化和大深度方向发展。过去,桥梁的深基础均采用沉箱、沉升施工法,七十年代以来,由于施工机械和施工技术的提高、采用钻孔灌注桩和管柱桩正逐年增多,并且使用更广泛,因为灌注桩不受地质条件的限制、噪音小,桩径和 Pile foundation is one of the most widely used and rapidly developed basic forms in the basic engineering at home and abroad. Its function is to transfer the vertical and horizontal loads to the structure and the bending moment to the lower and surrounding foundation. In foreign countries, since the 1970s, due to the exploitation of seabed oil, the construction and expansion of large ports and deep-water wharves, the construction of large-scale highways and railway bridges, new problems have been raised in the development of pile foundations, that is, to large-scale and large Depth direction. In the past, the deep foundation of the bridge used the caisson and settlement method. Since the 1970s, due to the improvement of construction machinery and construction technology, the use of bored piles and pipe piles has been increasing year by year and is more widely used. Not subject to geological conditions, noise, diameter and pile