地壳应变场观测中体应变与面应变转换系数的计算

将钻孔体应变仪与分量式应变仪的观测资料在面应变平台上进行整合，对于解决目前两种应变仪观测数据的评估、分析、处理和地震预报问题有实际意义．根据潘立宙-陈沅俊和Evertson理论及弹性力学知识，分别建立了平面应力作用下体应变和面应变观测的力学模型，推导了观测钻孔、空孔和无孔岩石体应变与面应变转换系数的计算公式，发现它们都可以归结为同一公式描述，差异仅在于k（体应变仪钢筒内壁或无孔岩石面应变与空孔岩石面应变之比）的取值不同．用Evertson理论推导的公式与空孔岩石情形相近，当岩石弹性模量为4times;1010——8times;1010 Pa时，二者都可以看成是对潘-陈公式的一种简化、近似计算；无孔岩石的情况则相当于在岩石弹性模量为1times;1010 Pa时对该式的一种估计. 文中结合实际情况对转换系数的各种影响因素进行了详细分析． 

Conversion factors from volume to area strain in crustal strain observation

This study aims at integrating the observational data recorded by borehole volume strainmeters and component borehole strainmeters on the area strain basis.This is helpful for current data evaluation,data processing and analysis,and earthquake prediction.Based on the Pan-Chen model ( Pan;Chen and Yang), Evertson theory and theory of elasticity,both volume strain and area strain models were set up under area stress.In addition,we have derived similar formulas for calculating transform coefficient between volume strain and area strain in observation hole,empty hole and non-porous rock condition ,respectively.The difference only lies in the factor k ( ratio of volume strain gauge on the steel cylinder wall or non-porous rock surface strain to area strain of the empty hole rock) .The theoretical formula derived from Evertson model is close to the case of empty hole rock with the rock elastic modulus ranged from 4×10 10 Pa to 8×10 10 Pa.Both results may be regarded as a simplified Pan-Chen model.For non-porous rock,the factor k may be predicted by taking rock modulus as 1×10 10 Pa.This paper discussed some factors related to transform coefficient based on real observation data.