小刚度劲性水泥土墙基坑支护的机理及模型试验

An Experimental Study of Models on Small H-Steel Soil-cement Wall Foundation Pit Bracing Mechanism

根据相似理论,通过小刚度劲性水泥土模型梁弯曲试验,研究了小刚度劲性水泥土梁中型钢与水泥土间的共同作用机理。提出水泥土及型钢相对刚度贡献系数概念,给出了组合结构的刚度贡献系数的取值,得出了组合梁开裂的极限挠度。结果表明:水泥土对组合结构的刚度具有很大贡献,水泥土开裂前后,型钢和水泥土对刚度的贡献都将发生变化。黏土水泥土、砂土水泥土和型钢间摩阻力与水泥土的强度成正比。双根型钢端部不同组合形式对水泥土刚度贡献系数及开裂的极限挠度影响不大。从共同作用机理分析认为,双根型钢铰接梁更适用于实践工程。

Some small section steel soil-cement walls are applied to foundation pit support instance. But there isn＇t acquainted with the wall＇s action mechanism. Through the bending experiments on small H-Steel soil-cement model beam, based on the similarity theory, the combined action mechanism of section steel and soil-cement in the model beam is set forth in this paper. The experiments showed that the soil-cement made great contributions to the ri- gidity of compound beam and also showed that both section steel＇s and soil-cement＇s contributions to the rigidity changed before or after the soil-cement cracking. Therefore, the con- cept is given of soil-cement and section steel relativity rigidity contribution coefficient, the rigidity formula of compound beam and the acquisition value of the rigidity Contribution coeffi- cient. The frictional resistance is obtained between the clay （or sand） soil-cement and the section steel. This frictional resistance is a direct proportion to the soil-cement strength. The different compound form of double section steel ends has a little influence on＇the soil-cement rigidity contribution coefficient and the cracking ultimate deflections. The cracking ultimate deflections of the compound beam are also obtained. It concludes that the double section steel hinged girder is more applicative in the practice under the analysis of combined action mechanism.