接触预压式元件钻孔变形法地应力测量数值处理

NUMERICAL TREATMENT OF MEASURING GROUND STRESS BY THE BOREHOLE DEFORMATION METHOD USING PRE-PRESSED PROBES OF CONTACT TYPE

在现有的采用接触预压式元件的钻孔变形法地应力测量中，不论是用哈斯特率定法还是围压率定法，在计算孔壁的折算位移时都存在着不足。１９８４年潘立宙首先指出了这些不足，并给出了计算孔壁折算位移的精确公式［１］。但由于公式中的某些参数不能直接获得，所以公式一时无法应用于实际测量。本文通过有限元法的数值计算，确定了文献［１］的计算公式中的参数值，从而得出了用以往方法计算折算位移所产生的误差。又经过数值的量级比较，明确了文献［１］的公式中所考虑的那些对计算折算位移有影响的因素的主次。

n current measurement of ground stress by the borehole deformation method using pre-pressed probes of contact type, the calibration of probes have been made by Hast's method and by mid-confining pressure method. Both methods have some defects in the derivation of reduced displacements. In 1984, Pan clarified it and gave the accurate formulas (See Ref. [1]). However. the formulas can not be used in practical measurements unless the parameters involved in them are numerically expressed. This paper has worked out the numerical values of the parameters through calculation with Finite Element Method. The error of traditional formulas have been estimated. By analyzing the numerical results, the majorfactors which effect the accuracy of reduced displacements as defined in Ref. [1] have beenrevealed.