Drill ( flushing, dig ) pile from the nineteen sixties, beginning in Henan province Nanyang region since the development application, because of its many advantages, has been widely used in soft soil, loess, including soil, expansive soil and other special types of foundation and industrial, civil, municipal, railway, highway, port and other types of Engineering practice. And precast pile, bored pile construction of no noise, no vibration, on the surrounding buildings and small environmental impact, pile diameter, buried deep, large bearing capacity. China's drilling pile maximum diameter of pile has reached 4000mm, maximum deep pile has reached 104m, and the steel pipe pile maximum diameter of 1200mm, the largest pile of prestressed concrete pipe pile with deep 83m, maximum diameter of 1300mm, the biggest pile depth 40m.
Along with our country socialist construction is booming, with high-rise buildings, large span bridges on the rise, the bearing capacity of pile foundation with higher requirements. Large diameter bored pile therefore gets rapid development, pile length and pile diameter also do bigger more. However, in the existing various methods of pile, bored pile has many advantages and is widely used in construction, but it is hard to avoid the impact of mud, which not only reduces the bearing capacity of pile expectations, but also caused a serious waste of materials. Manual hole digging pile is difficult to achieve greater depth, its bearing capacity is also difficult to just as one wishes. In view of bored pile in this situation, how to improve the pile construction technology level, make the input material to be more reasonable to use, so as to greatly increase the bearing capacity of single pile in engineering field, have become hot issues in recent years.


概述
鉆（沖、挖）孔灌注樁，從20世紀(jì)60年代初在河南省南陽地區(qū)研制應(yīng)用以來，因其具有眾多的優(yōu)點(diǎn)，已廣泛應(yīng)用于包括軟土、黃土、膨脹土等特殊土在內(nèi)的各類地基和工業(yè)、民用、市政、鐵路、公路、港口等各類工程實(shí)踐中。和預(yù)制樁相比，鉆孔樁施工時(shí)無噪聲、無振動，對周圍建筑及環(huán)境影響小，樁徑大，入土深，承載力大。據(jù)文獻(xiàn)[1]統(tǒng)計(jì)，我國鉆（沖）孔樁最大樁徑已達(dá)到4000mm，最大樁深已達(dá)104m，而鋼管樁最大樁徑為1200mm，最大樁深為83m，預(yù)應(yīng)力混凝土管樁最大樁徑為1300mm，最大樁深為40m。
　　隨著我國社會主義建設(shè)事業(yè)的迅速發(fā)展，伴隨著高層建筑，大跨度橋梁的興起，對樁基礎(chǔ)的承載力有了更高的要求。大直徑灌注樁因此得到快速發(fā)展，樁長和樁徑也越做越大。然而，在現(xiàn)有的各種成樁方法中，鉆孔樁雖有許多優(yōu)點(diǎn)而被廣泛采用，但在施工中卻難以避免泥漿的影響，這不僅降低樁承載力的期望值，而且造成材料的嚴(yán)重浪費(fèi)。人工挖孔樁因難以達(dá)到更大的深度，其承載力也難盡如人意。鑒于灌注樁的這種現(xiàn)狀，如何提高樁的施工工藝水平，使投入的材料得到更為合理的利用，以大幅度提高單樁承載力，就成為工程界備受關(guān)注的熱點(diǎn)問題。