钻孔应变观测影响因素的数值模拟分析  

NUMERICAL SIMULATION OF AFFECTING FACTORS ON BOREHOLE STRAIN-METER OBSERVATION

作　　者：李玉江[1] 陆远忠[1] 陈连旺[1] 詹自敏[1] 叶际阳[1] 

机构地区：[1]中国地震局地壳应力研究所,北京100085

出　　处：《大地测量与地球动力学》2011年第1期34-38,43,共6页Journal of Geodesy and Geodynamics

基　　金：中央级公益性科研院所基本科研业务专项(ZDJ2009-13;ZDJ2010-12)

摘　　要：利用有限元数值模拟方法,研究在非均匀地应力作用下,钻孔开挖前后区域应力场的变化特征,并探讨钻孔开挖后岩石、水泥、探头的弹性模量、泊松比及水泥的厚度与膨胀系数的变化对分量应变及面应变观测的影响。研究结果表明:钻孔开挖造成区域应力场扰动的范围大概为1.5倍孔径。在"探头-水泥环-围岩"系统中,各参数的变化对应变观测的影响程度不同,但分量应变对外界载荷的响应趋势基本一致。在均匀地应力作用下,水泥厚度对应变的影响与水泥的弹性模量有关,且随着水泥膨胀系数的增加,面应变存在减小的趋势。On the basis of the ＂casing-cement sheath-formation＂ system,the three dimensional finite element model was built.With this model,and under the non-uniform stress conditions,the stress change characteristics before and after the borehole drilling were studied and the effects of the changes of the elastic modulus of the rock,cement and sonde casing,the Poisson ratio,the cement thickness and the expansion coefficient of the system on the component strain and plane strain after drilling were inquired as well.The results indicate that the influence incidence from the borehole drilling is probably 1.5 times as big as the aperture.The influence of each parameter’s change on the strain is different,whereas the component strain response trend to the exterior load is primarily alike.Otherwise,under the uniform stress conditions,the effect of the cement thickness on the strain is related to the cement elastic modulus,but the plane strain is of negative correlation with the expansion coefficient.

关 键 词：分量应变 应力场 弹性模量 面应变 数值模拟 

分 类 号：P315.72[天文地球—地震学] TH762[天文地球—固体地球物理学]