Study On Soft-soil Pile Foundation Engineering, Construction And Test For Multi-storey Building

The design approach, which is based on the working mechanism that the soil works together with the piles and bears parts of the upper structure loads, has great social and practical significance. In order to make better use of the design, this paper conducts a substantial study with regard to the foundation models, the design models and the field tests and verifications.1. Existing foundation models are analyzed and generalized in accordance with the stress mechanism. Some linear elastic foundation models available are chosen to process the pile foundation design, mainly about the Winkler foundation model, the elastic semi-space model and the tiered foundation model.2. The creep and the concretion of the soil under either the natural conditions or the external loads are considered to approach the actual impact. Moreover, several settlement models and their computing methods are studied, including the simple theory method and the semi-theory & semi-experience method.3. Different design models are analyzed and compared to find the optimum model fitted to engineering application, which is based on the stress mechanism and the settlement models of the piled soil. In addition, the friction piled foundation, creep pile foundation, the piled raft foundation and the padded pile foundation are the main models to be analyzed.4. Thorough tests and studies are conducted on the construction project designed with the friction piled foundation, in order to identify the working rules of the soil and the settlement. The adoption of the reverse-order pile construction effectively coordinates the deformation on the interface of the piles and the soil with raft. According to the test results under varying load, the ratio of loads on the piles and the soil is concluded, and a better basis for the load computing is gained. The rule of loads and settlement is concluded from numbers of settlement observation points'data. And in actual construction, this rule could be used to prevent immediate settlement under the accelerated load, and also, the serious result of the soil destruction could be avoided. At last, a proper method of settlement computing is derived from the identified rules, which can be used to guide the practical construction work, of course, meeting the compulsory standards of the settlement control well.