利用钻孔形变测量介质中应力场——有关地应力测定中的元件和测量数据处理的讨论

在坑道中或地表上,对地壳形变所进行的各种观测,是了解地下应力活动的重要手段。目前,国内外开展在岩石中钻孔进行应力测定存在的问题,是受局部偶然因素的影响较大,需要注意克服。 求取地下岩体中的实际应力值,不仅是地震预报工作的需要,也是建筑、水坝、隧道、

MEASUREMENT OF STRESS FIELD IN SITU BY MEANS OF BORE HOLE DEFORMATION

For determining the absolute stresses in rock medium and their variation with time,the method of measuring the deformation of bore holes in situ is of increasing interest recently.In order to design a sensitive measuring unit,it is necessary to know those factors controlling the measuring unit.It is also important to examine the physical meaning of the values recorded when the measuring unit is embedded in the radial direction of the hole.It is concluded that the stress components cannot be measured directly,because the boring hole has disturbed the stress field （stress concentration）.The stress field can only be measured from the deformation of the hole.When a measuring unit of certain rigidity is used,the stress field around the hole is disturbed,and the values recorded depend on the secondary contact force between the measuring unit and the Bore hole wall.This force is proportional to the radial displacement of the wall under free conditions （before embedding the unit）; thus,the stresses may be computed.By analysing the force and deformation sensitivities of the measuring unit and its resistance to deformation,the characteristics of the measuring unit can be improved.