粉喷桩在软基处理中的应用.rar

粉喷桩在软基处理中的应用
粉喷桩是粉体喷射深层搅拌法的简称，它是深层加固处理技术的一种。其原理是通过专用的深层粉体喷射搅拌机，将粉状加固料如水泥、石灰粉，用压缩空气喷入地基深部，凭借搅拌机的回转钻头叶片使加固料与原位软土混合，就地搅拌形成具有整体性、水稳性及一定强度的桩体，桩体中的加固料与软土产生一系列物理化学反应，使软土硬结，从而使桩体与桩间土一起组成复合地基，起到加固地基的目的。
　　工程概况
　　桥址地质条件：同三线宁波段K3+782桥基条件极差，通道桥设计要求地基承载力不小于150Kpa，桥址工程地质情况：原地基承载力远远满足不了设计要求，如用打塑料排水板超载预压法处理，预压期要6个月，不能满足工期要求，综合各种处理方法及影响因素，最终确定用粉喷桩加固处理软基。
　　地基处理范围：横桥向28米，顺路方向12.8米（即中心桩前后各6.4 米）。粉喷桩的平面布置为等边三角形，边长为1.3米（即桩中心距离），桩直径0.5 米，桩长9 米，采用325水泥，复合地基承载力不小于150kpa。
　　室内配合比确定水泥用量
　　由于水泥加固土桩体的质量与天
Soft Foundation Treatment
DJM is a Powder Jet Mixing law referred to, it is a deep reinforcement technology. The principle is through a dedicated deep powder injection mixer, will be reinforced materials such as cement powder, lime powder, spray with compressed air deep into the ground, with the mixer of the rotary drill bit blade made of soft soil reinforcement material and in situ mixing, in situ mixing formation integrity, water stability and a certain intensity of the pile, pile in soft soil reinforcement material and produce a series of physical and chemical reaction, so that the soft soil induration, so between the soil pile and the pile composite foundation with the composition, from to reinforce the purpose of the foundation.
Project Overview
Bridge site geological conditions: the same three-lane section of K3 +782 Ningbo Bridge Foundation in very poor conditions, the channel bridge design bearing capacity of not less than 150Kpa, bridge site engineering geological conditions: bearing capacity falls far short of the original design requirements, such as the use of play plastic drain Precompression Preloaded on to 6 months, can not meet the schedule requirements, integrated approach and the influence of various factors, to finalize the deal with soft pile reinforcement.
Ground treatment area: 28 m transverse to the lift on the direction of 12.8 meters (namely, before and after 6.4 m of pile). Pile layout of an equilateral triangle, side length of 1.3 meters (ie pile center distance), 0.5 m diameter pile, the pile length 9 meters, with 325 cement, composite foundation is not less than 150kpa.
Determine the amount of cement mix room
As the pile of cement stabilized soil quality and day