珊瑚礁不同地貌带有着不同的工程地质特征和力学特性。为探究珊瑚礁地基的工程力学特性及其发育规律，在西沙永兴岛不同地貌单元开展了浅层平板载荷试验、深层螺旋板载荷试验、压实度测试以及回弹模量试验，获取了珊瑚礁不同地貌的地基承载力、变形模量、回弹模量等工程力学参数。试验结果表明：人工填筑的钙质土地基承载力和变形模量明显高于天然形成的礁坪相地基和沙坝地基，其承载力特征值可达320～360 kPa，变形模量在95～200 MPa之间，且地基的沉降量很小，满足一般低层建筑物对地基承载力和变形的要求；在荷载作用下，钙质土地基的沉降是瞬时完成的，载荷试验可采用快速加载法；在地下水位以上地基承载力随着深度增大逐渐增加，但在地下水位以下承载力和变形模量明显减小。钙质土地基压实度在87%以上时回弹模量达到472～730 MPa，且回弹模量随着压实度的增大而增大。

Different geomorphologic zones of coral reef demonstrate different geological engineering behaviors and mechanical properties. In order to investigate the engineering behaviors and its regularity, a series of tests including plate loading test, deep spiral plate loading test, compaction test and resilience modulus test is conducted on different zones in Yongxing Island, South China Sea. Engineering mechanical parameters including bearing capacity, deformation modulus, rebound modulus of coral reef are obtained. The test results show that the bearing capacity and deformation modulus of artificial calcareous soil ground are higher than those of reef flat foundation and sand bar foundation. The bearing capacity of artificial calcareous soil ground ranges from 320 to 360 kPa, and its deformation modulus ranges from 95 to 200 MPa. The bearing capacity of ground satisfies the requirement of low-rise buildings. As settlement of calcareous ground accompanies instantaneously under loading, fast loading method can be adopted in the plate loading test. The bearing capacity of subgrade above underground water table increases with increasing depth, but decreases below underground water table. The modulus of resilience increases with compaction. It can reach a range from 472 to 730 MPa with the degree of compaction over 87%.