不同含水和密实状态下珊瑚砂地基承载特性试验研究

珊瑚砂工程性质特殊，研究珊瑚砂地基的承载特性对岛礁工程建设具有重要意义。通过不同相对密实度（50%、65%、72%、80%和85%）、不同含水状态（干燥和饱和）及水位升降等工况下的珊瑚砂地基平板载荷模型试验，研究相对密实度和含水状态对珊瑚砂地基承载特性、颗粒破碎、分层沉降和土压力传递规律等的影响。结果表明：随着相对密实度的增大，干燥状态下珊瑚砂地基极限承载力增大，沉降减小；相对密实度80%以上的珊瑚砂颗粒破碎较明显；承压板正下方的土压力随深度增大而减小。饱和珊瑚砂地基的极限承载力约为干燥状态的44%，地基破坏时的沉降约为干燥状态的2倍，两次水位升降对地基承载力和沉降影响较小；距离承压板中心不同位置处，饱和（含水位升降）与干燥状态下珊瑚砂地基分层沉降呈现出不同的规律；3种工况下土压力传递规律相似。

Experimental study on bearing characteristics of coral sand foundation under different water content states and relative compactnesses

The engineering properties of coral sand are special, so it is important to study the bearing characteristics of coral sand foundation for island construction. The influences of relative compactness and water content state on the bearing deformation characteristics, particle breakage, layered settlement and the pattern of earth pressure transfer of coral sand foundation are studied through the plate loading model test of coral sand foundation under different working conditions, such as different relative compactness (50%, 65%, 72%, 80% and 85%), different water content states (dry or saturated) and water level variations. The results show that the bearing capacity of coral sand foundation increases and the settlement decreases with the increase of relative density in dry condition. The coral sand particles are broken more significantly while the relative compactness is greater than 80%. The earth pressure directly below the bearing plate decreases with increase of depth. The bearing capacity of coral sand foundation in saturated state is about 44% of that in dry state, the settlement in the failure is about 2 times of that in dry state, and the influence of two times of water level variation on the bearing capacity and settlement of foundation is small. At different locations from the center of the bearing plate, the developments of the layered settlement of coral sand foundations in saturated, water level variation and dry state are different. The pattern of earth pressure transfer is similar in the three states.