Studies On The Anti-uplift Behavior Of The Suction Caisson In Saturated Sand

Energy is the foundation and backbone of modernization process. People are relying more on energy in the wake of promoting modernization more quickly. However, the expense is becoming higher and higher to exploit energy on land, the enormous potential of offshore area attracts people’s attention gradually. Suction caisson is one of most common foundations for offshore structures. Suction caisson has some advantages such as lower construction cost, easier penetration, reusable utility, lower requirement for geological survey and shorter construction time. Due to these advantages, many researchers pay attention to the related scientific topics in the past20years.A series of centrifugal tests are conducted to study the pullout capacity of suction caisson in saturated dense sand, and some regulars are mainly summarized. Firstly, this thesis makes comment on the advantages and disadvantages of centrifugal tests, and on the basis of it, the experimental process is described with detail. Then all instruments used in centrifugal tests are introduced comprehensively, and their precision and mechanical properties are listed. By analyzing the test data, some key influence factors, including loading position, loading angle and sand’s relative density on the bearing capacity of suction caisson are discussed in this paper. It is given that the turning center’s range of caisson under inclined loading. The caisson behavior is shown under different load conditions such as various loading angles and positions. And the optimal load condition is pointed out at given states. Another important part of this paper is to analyze the caisson’s displacement process subjected to pullout loading and the components of caisson’s vertical bearing capacity. Three phases are put forward to describe suction caisson’s anti-pullout behavior and displacement process, mechanical characteristics of three phases are discussed briefly, and the control bearing capacity is suggested.A lot of steps need to be done in order to accomplish these centrifugal tests, including sample preparation and saturation, caisson’s penetration at1g level, relative sensors’ calibration and installation, etc. There are some systemic error due to the precision of experimental apparatus, and some other errors coming from test’s operation process, inevitably. These errors are discussed in this paper comprehensively. And methods are presented to control errors.