上世纪80年代中期发展起来的深钻孔套芯应力解除测量法，为工程提供了大量的不可缺少的地应力实测资料，其中测量深度突破300m的有3次。在阐述这种地应力测量方法的测试技术以后，详细地介绍了第一次测深突破300 m的三峡工程船闸区的测量成果，并重点剖析了该地区的地应力场，同时简单地介绍了另2次测深突破300 m测量成果的工程应用。用此法得到的测量成果被三峡船闸区其它钻孔的测量成果所验证。

The overcoring method used in deep borehole which was developed in the mid-term of 1980s has provided a large amount of measured data of geostress. Among these measurements there were only three times of measuring depth over 300 m. In the paper, after presenting the technique of this measuring method, the measured results of measuring depth over 300 m of the first time at the lock area of the Three Gorges Project(TGP) are introduced, and the geostress fields of this area are emphatically analyzed. At the same time, the measured results of other two times of measuring depth over 300 m for two practical engineerings are briefly presented. At last, measured results obtained by the overcoring method are proved by the data gained from the other boreholes of TGP’s lock area.