三维钻孔应变的力学模型

讨论了两个问题：（１）三维圆孔问题的力学模型。论证了常用的平面弹性力学圆孔问题的钻孔应变公式并不能满足三维弹性力学平衡方程。为此重新推导出三维空孔问题的解，进而可得到有底空孔、有底耦合封固、有底顶头加力等几种边界条件的钻孔应变解。（２）在边界条件上，实际地球潮汐形变应力与三维圆孔问题力学模型的应力有差异。论证了在目前钻孔应变测量的精度情况下，边界条件的这一差异不影响三维圆孔问题力学模型在应变固体潮中的应用

3-D MECHANICAL MODEL OF BOREHOLE STRAIN

First, the 3-D mechanical strain models of borehole in slab are discussed. The boundary conditions are as follows: (1)the possitive stresses at top and bottom boundaries of the borehole are zero, (2) there is horizontal principal stress on the wall of the borehole. The boreholes can be divided into four kinds: a. borehole that drills throughout the slab, b. borehole with bottom, c. borehole filled with coupled medium, d. to force to the side-well of the borchole-with-bottom with a transducer. The strain solutions of the borehole are computed under the various boundary conditions.It is indicated that there are two different boundary conditions between the tidal deformation of the practical earth and the 3-D mechanical strain model of the borehole in the slab.(1)there is vertical tidal deformation stress on the bottom of the practical borehole on the earth.(2)the horizontal tidal deformation stress of the earth is relative to the depth. Finally,the magnitudes of the tidal strain in the borehole are computed.It is shown that the differences described above don't have influence on application of 3-D mechanical strain models of the borehole in the slab to observation of the tidal strain of the borehole under present measuring accuracy.