Application Research Of Deep Mixing Pile In Western Coast Of Qingdao

Deep mixing method is a method using special machinery-all kinds of deep mixers to forcefully mix the curing agent (cement grout or cement powder) with foundation soil along the depth to form cement-soil pile to reinforce the foundation. Its property indicates it is a kind of pile between rigid pile (bored concrete pile, cast-in-place concrete pile, precast concrete pile and steel tubular pile, etc.) and flexible pile (gravel pile, sand pile and lime-soil pile, etc.), which rigidity, compressive strength and anti-lateral pressure effect are less than rigid pile, but larger than flexible pile. Deep mixing method is applicable to the treatment of silt, silty clay, silty soil, clay soil and sand soil, etc. soft foundation. It can reinforce the foundation, according to requirements, to massive, columned, wall-shaped and grille-shaped cement soil, which is mainly used in forming compound foundation, supporting and protecting structure of footing groove, water stop sheet in foundation and other uses.This article mainly discusses the application matters of deep mixing pile in the treatment of compound foundation in the construction works of Qingdao western coast. It researches the selection of the calculation parameters in the bearing capacity of compound foundation. After contrast with the calculation formula in "The Rule of Treatment Technique for Construction Foundation" and statistic calculation in project example, it initially confirms the value selecting range applicable to this area. One of the research methods is to analyze the deposit environment and cause of formation of the stratum of this area to find its stratum combination characteristic. It also analyzes the applicability of the deep mixing method in this area and the characteristic of the cement soil it formed, and concludes the combination relationship between the intensity of cement soil mixing pile and the stratum of Qingdao western coast.The second methods is by the project example, it observes there is great difference between the designed value and actually measured value of the bearing capacity of deep mixing pile compound foundation. After analyzes the reason, it finds, in the calculation formula of the compound foundation's bearing capacity, the value selecting range of the reduction factor ( ) for calculation of the pile body's intensity is on the small side. After repeatedly calculation, contrast and analysis, it gets the value selecting range applicable to this area, which provides a reliable basis for designing the bearing capacity of the deep mixing pile compound foundation under the condition of the stratum combination of Qingdao western coast.