【摘要】 通过上覆人工硬壳层、下卧淤泥质黏土层的双层地基室内模型试验,结合以往研究成果,配制25mm厚的硬壳层,选取基础尺寸及水泥掺入比作为参数,研究人工双层地基在不同基础尺寸以及水泥掺入比下的承载性能及固结沉降特性,论证淤泥质黏土层利用的可行性。设计了9组室内模型试验,试验结果表明,其他条件不变,水泥掺入比的增加,提高了双层地基的极限承载力,但是增加的作用逐步减弱;同时减小了沉降量,但是对于沉降的遏制作用也随着水泥掺入比的增加而减弱。基础底面尺寸与硬壳层厚度的比值(宽厚比)对于破坏模式有较明显的影响,宽厚比为2,且水泥掺入比不超过5%时,硬壳层为冲剪破坏;宽厚比≥4时,破坏模式表现为折断破坏。因此,考虑工程经济性原则,选择合适的水泥掺入比,能够有效利用硬壳层的承载作用;对于宽厚比的研究表明,基础尺寸的设计要尽量避免硬壳层出现冲剪破坏,避免导致错误估计硬壳层承载力,造成突发的基础下沉。更多还原

【Abstract】 Through double-layered foundation indoor model test,using man-made crust above and muddy layer under,combining the previous research achievements,with preparation of 25 mm thick crust layer,basic size and mixing ratio of cementas aparameter,the artificial double foundation’s bearing capacity and characteristics of settlement will be discussed in different sizes,to prove the exploitable feasibility of muddy clay. Nine groups of indoor model tests indicate that when the other conditions unchanged,the increase of the cement mixing ratio improve the limit bearing capacity of two-layer foundation. But decrease the effect of increase gradually,at the same time,the settlement amount is decreased,but the restraining effect of settlement is reduced with the increase of cement incorporation ratio. The ratio between foundation size and thickness of overlying crust( width-to-thickness ratio) has obvious effect to failure mode. When the ratio is 2,and cement ratio is less than 5%,the crust turns into punching shear failure; When the thickness ratio is greater than or equal to 4,the failure mode is broken. Therefore,considering the principle of engineering economy,choosing appropriate cement incorporation ratio can effectively make use of the bearing function of the hard shell layer. The research on the thickness ratio shows that the design of the base size should avoid the shear failure of the hard shell layer,which leads to the error estimation of the bearing capacity of the hard shell,causing the sudden foundation sinking.更多还原