黏土中桶形基础负压下沉阻力及土塞发展试验

Experiment on Penetration Resistance and Soil Plug Development During Suction Caisson Penetration in Soft Clay

桶形基础负压下沉时下沉阻力和土塞发展是桶形基础施工中的两个关键性问题.针对此问题,进行了不同土体中桶形基础下沉特性的模型试验,测量试验过程中土塞隆起高度、桶体下沉位移及施加负压值的大小.试验结果表明,当施加的负压大于所需负压时桶体才会下沉,并且土塞是阻碍桶体下沉的最主要原因.在负压下沉过程中,土塞隆起参数分别为74%,和105%,,并且当反向地基承载力破坏发生时,更多土体将会进入桶内.在实际工程中,桶内土塞的发展应作为负压下沉时施工控制的关键技术指标,并且需要对其进行实时监控,避免施工上的困难和对桶体稳定性的影响.

Penetration resistance and soil plug development are two critical issues in construction during suction caisson penetration.Aiming at these problems,model tests were carried out to study the behavior of suction caisson penetration in different types of soils.The height of soil plug,displacement of suction caisson and applied suction pressure are measured during the model tests.The model tests show that the caisson began to install when the applied suction was greater than the required underpressure,and the soil plug is one of the key factors that interrupted the penetration process of caisson.During the process of suction penetration,the soil plug parameters were 74%, and 105%, respectively,and more volume of soil would enter the caisson when the reverse bearing failure occurs.In practical construction,the development of soil plug inside caisson should be used as a key technical index during suction penetration construction.Moreover,to avoid difficulties in construction and instability of suction caisson,real-time monitoring should be carried out on soil plug heave.