For the mooring line embedded in seabed, the axial soil resistance directly affects the tension transfer characteristic along the mooring line. Effective width parameter E_t was commonly adopted to assess the axial resistance of anchor chain. However, neither the chain axial resistance nor its effective width parameter in sand has been fully understood. In this two-part paper, a series of axial loading tests between chain and sand were conducted. Part I shows the monotonic loading results, and Part II aims to study the cyclic loading behavior. In Part I, a kind of novel chain-soil interaction apparatus was first developed, and the method for acquiring the axial resistance was proposed. On this basis, the influences of confining stress, chain nominal diameter, sand particle size and relative density were investigated in detail. It is found that when the chain axial resistance is fully mobilized, the effective width parameter in sand ranges from 8.91 to 11.94. The statistical average value E_t=10.34 is quite close to the normalized chain perimeter P_c=10.37(3.3π). Then, an example was given to show how to calculate the chain profiles in sand using the proposed E_t expression. A method for calculating the chain profile in sands was verified by the centrifuge test results. The calculation results show that higher E_t values lead to larger force inclined angles at the padeye. Under the condition, the anchor will suffer larger vertical loads due to the increase of the inclination angle.

对于嵌入海床的系泊缆，轴向土阻力直接影响沿系泊缆的张力传递特性。有效宽度参数 E _t常用来评估锚链的轴向阻力。然而，无论是链条轴向阻力还是它在沙子中的有效宽度参数都没有被完全理解。在这篇由两部分组成的论文中，进行了一系列链条和沙子之间的轴向载荷试验。第一部分显示单调加载结果，第二部分旨在研究循环加载行为。第一部分首先研制了一种新型的链-土相互作用装置，并提出了轴向阻力的获取方法。在此基础上，详细研究了围压、链条公称直径、砂粒粒径和相对密度的影响。结果表明，当链条轴向阻力充分调动时，砂土中的有效宽度参数范围为8.91~11.94。统计平均值 E _t=10.34 非常接近归一化链周长 P _c =10.37(3.3π)。然后，给出了一个例子来说明如何使用所提出的 E _t表达式计算沙子中的链剖面。离心机试验结果验证了一种计算砂中链剖面的方法。计算结果表明，较高的 E _t值导致大眼的力倾斜角。在这种情况下，由于倾斜角的增加，锚将承受更大的垂直载荷。