【作者】 张重远；

【导师】 吴满路；

【作者基本信息】 中国地质科学院 ， 地质工程， 2013， 硕士

【摘要】 原地应力状态是固体地球最重要的物理参数之一。进行地应力测量,研究地壳应力状态,对于地球动力学问题和工程应用问题具有十分重要的意义。国际岩石力学学会推荐过应力解除法和水压致裂法作为地应力测量的两种主要方法。这两种方法都属于平面应力测量,其测量准确度和适用性一直是本研究领域很关注的问题之一。本论文依托于“原地应力测试技术方法试验研究”项目,主要工作在河北易县紫荆关试验场完成,作者参与了全部的野外应力对比测量工作。基于该工作,本论文体现的研究内容如下：(1)收集资料和文献,研究总结压磁应力解除法的理论依据和数据处理方法,并对已有的压磁应力解除系统进行分析,归纳总结新型压磁应力解除系统的改进和创新点；(2)总结水压致裂法测量数据处理方法,并对水压致裂测量试验数据选择合适的方法,综合岩芯情况以及测量曲线分析,最终确定合理的应力值；(3)完成3个钻孔中4个深度的压磁应力解除法地应力测量和4个钻孔不同深度水压致裂地应力测量,并创造了该方法的国内外最大测量深度：(4)完成了压磁应力解除法和水压致裂法地应力对比测量分析,探讨了两种方法的测量可靠性、适用性以及影响因素。通过上述工作,得出以下几点认识和看法：(1)新型压磁应力解除系统比传统系统有了很大创新和进步,基于该系统的压磁应力解除法地应力测量效率更高,深度也比以往有很大提高,达到国内外最深的213.6米。(2)针对4个钻孔相同(相似)深度段的压磁应力解除法和水压致裂法地应力测量结果,对比研究所得地应力状态,可知：①压磁应力解除法在浅孔中(约200m以上)测量效果较好。以其为比较基准,和水压致裂法测得的最大水平主应力相差基本在10%以内,最小水平主应力相差36%以内,一致性比较好；最大水平主应力方向基本和区域应力场主应力方向吻合；②水压致裂法在4个浅孔中获得了较为一致的应力变化趋势,但在相近的深度,不同钻孔中测量点应力值有不同程度的差别,不论是岩体完整段或者是原生裂隙发育的地方,这体现了应力场的复杂性；最大水平主应力方向为NW40°～50°,和区域应力场主应力方向一致；③不同钻孔相近深度的最大和最小水平主应力值的比较说明,测量点附近存在裂隙会影响测量结果,若存在破碎带则影响更大。完整可以很好地赋存原地应力,相近深度测量点得到的应力值也比较接近。更多还原

【Abstract】 In-situ stress state is one of the most important physical parameters of the solid earth. Carrying out stress measurement and studying stress state in the crust are of considerable interest for the issues of earth dynamics and engineering application. ISRM has recommended overcoring and hydraulic fracturing as the major methods for in-situ stress measurement. The two methods are both belong to plane stress measurement, however, their accuracy and usability has always been a concerned problem in the field.This paper based on the "an experimental study of in-situ stress measurement techniques" project and main tasks were done in experimental field in Zijingguan, Yixian of Hebei Province. The author has joined all the stress comparison measurements in the field. Based on the jobs, what this paper has completed are as following:(1) A good many of data and literature were studied to summarize the theory and data process of piezomagnetic overcoring. Analysis for the old piezomagnetic overcoring system were done and summaries for improvements and invocations of the new version were shown;(2) Data process methods of hydraulic fracturing were summarized. Proper methods in this study were chosen, combined with drilled cores and measurement curves, to determine the final stress values;(3) Piezomagnetic overcoring stress measurements at4different depths in3boreholes and hydraulic fracturing at different depths in4boreholes were finished. The deepest piezomagnetic overcoring measurement was done in the world;(4) Comparison measurement analysis for piezomagnetic overcoring and hydraulic fracturing was conducted and reliability, usability and influence factors of the two methods were discussed.By what have done above, some conclusions can be drawn as following:(1) The new piezomagnetic overcoring systems has improved a lot than the old one. In-situ stress measurement based on the system was more effective and could work in deeper rock mass than before. The deepest depth it completed in the world was213.6m.(2) Based on comparison study of piezomagnetic overcoring and hydraulic fracturing stress measurements in the same or similarly depth in4boreholes, some conclusions can be obtained:①It was proven that, above200m, take piezomagnetic overcoring as reference, the difference between the maximum horizontal principal stress obtained from piezomagnetic overcoring and that from hydraulic fracturing, was less than10%, and as for the minimum horizontal principal stress was less than36%. Also, the principal stress direction agreed with that of regional stress field, stating that results of two methods measurement agree well with each other.②Hydraulic fracturing got the concordant stress change trend in4boreholes. However, different depths in different boreholes showed different stress values, not only for intact rock mass, but also for some place with pre-existing fractures developed, which indicated the complexity of stress field. The directions of maximum horizontal principal stress between NW40°～50°, which agreed with that of regional stress field.③Comparisons between the maximum and minimum horizontal principal stress at similar depths in different boreholes stated that if there existed fractures near the measurement sites, the measurement results were to be influenced and fracture zone affected more. Intact rock mass can store in-situ stress well and stress values obtained from similar depth were similar to each other, as well.更多还原