倒垂基准稳定性研究

分析了垂线的复位误差与垂线长度、张拉应力、浮体受到的粘滞阻力间的关系，研究了不同库水位对倒垂锚固点稳定性的影响，建立了倒垂组垂线之间的修正模型，并将其应用于实例。结果表明，不必布置很深的倒垂，只要用不同埋深的倒垂构成倒垂组，通过模型修正，就可有效地消除因库水位变化引起倒垂锚块不稳定而对测量结果所产生的影响，从而解决了过深倒垂不仅施工困难，而且会降低倒垂灵敏度的问题。

Benchmark stability of inverse plumb lines

The relationships between the reposition error of plumb lines and some concerned factors, including the length of plumb lines, stress, and floating resistance, are analyzed. The influences of different water levels on the stability of anchor points of inverse plumbs are studied. A modified model for inverse plumb lines is established and applied to practical projects. It is concluded that, in determination of the depth of plumb lines in high dams, the stability of anchor points and sensitivity of the inverse plumb line system should be synthetically considered, that it is unnecessary to install very deep inverse plumbs, and that the inverse plumb line group, consisting of inverse plumbs with different embedded depths, modified by the model, can effectively eliminate the influence of instability of anchor points at different water levels on the measured results. The model can help avoid difficulties in construction of very deep inverse plumbs and the decrease of sensitivity induced by very deep inverse plumb system.