利用岩石抗拉强度估算最大水平主应力的对比分析

发布时间：2018-01-13 21:31

  本文关键词：利用岩石抗拉强度估算最大水平主应力的对比分析　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

  更多相关文章： 水压致裂 最大水平主应力 双圆环直接拉伸 数值模拟 对比分析

【摘要】：钻杆式水压致裂原地应力测量系统的柔性对最大水平主应力的结果会产生很大的影响,提高最大水平主应力的测量精度对各种地下工程设计都具有重要意义。尝试通过室内试验测量岩石抗拉强度值估算最大水平主应力,并与通过经典水压致裂公式计算得到的最大水平主应力进行对比分析,期待找到一种室内试验替代方法避免系统柔性的影响,提高最大水平主应力的测试精度。在这一研究过程中,分别从以下几个方面展开:梳理了国内外岩石抗拉强度试验方法的研究现状及综合对比;进行室内双圆环直接拉伸试验并分析试验结果,初步探究双圆环直接拉伸试验的内环直径/试件直径、外环直径/试件直径、内环直径/外环直径的最优比范围;对双圆环直接拉伸试验的不同尺寸的试件模型进行数值模拟研究及对比分析,验证室内试验结果;室内试验数据与现场实测数据的对比分析。基于以上几个方面的研究,初步成果如下:(1)对于同一地区岩石不同的测试方法测得的岩石抗拉强度值差别很大。直接拉伸、弯曲拉伸、巴西劈裂,空心岩柱等试验理论完善,试验指导体系已经趋于成熟。其中直接拉伸试验的原理最接近岩石抗拉强度的定义。弯曲拉伸试验测得的数值偏大,影响因素多。巴西劈裂试验争论较大,影响因素颇多,但认可度高。空心岩柱试验近几年发展迅猛,试验指导体系日渐成熟。双圆环直接拉伸试验国内外研究颇少,缺乏系统的试验指导方案。(2)通过设计部分内外环直径的双圆环直接拉伸试验的试件进行室内试验,得出内环直径与试件直径比处于0.32~0.47,岩石外环直径与试件直径比处于0.53~0.69,岩石内环直径与外环直径比处于0.58~0.69时,获得的岩石抗拉强度值比较稳定可靠。(3)运用ABAQUS数值模拟软件对54个不同尺寸的双圆环直接拉伸试验的试样进行模拟发现:当外环直径/试件直径比的范围为0.53~0.74,内环直径/试件直径比0.32~0.48时,试件的应力分布状态比较均匀,理论上来说可以获得稳定可靠的岩石抗拉强度。同时验证了室内双圆环直接拉伸试验初步得到的试件内、外环直径/试件直径比范围的合理性。需要着重强调的是,当选择的外环直径/试件直径比数值偏大时,内环直径/试件直径的比也要对应的选择偏大一些。(4)对河北易县和山东红河两地获得的岩石进行室内试验估算最大水平主应力,与经典水压致裂公式计算得到的最大水平主应力对比分析发现:通过弯曲拉伸试验、圆盘劈裂试验(垫条法,2:1)、空心岩柱试验(1:1,注油)估算的最大水平主应力均大于现场实测的最大水平主应力50%甚至是100%以上,严重偏大。而圆盘劈裂试验(角锥法,1:1)、直接拉伸试验、空心岩柱试验(1:1,注水)估算的最大水平主应力略大于现场实测的最大水平主应力;双圆环直接拉伸试验略小于现场实测的最大水平主应力,都在可接受的范围内。圆盘劈裂试验(角锥法,2:1)获得的岩石抗拉强度离散性大,数据不稳定可靠。空心岩柱试验(1:2,注水)两地的对比结果不统一,需要进一步研究。
[Abstract]:Drill rod type hydraulic fracturing in-situ stress measurement system of the flexible of the maximum horizontal stress results will have a great impact, improve the measurement accuracy of maximum horizontal principal stress of underground engineering design is of great significance. To estimate the maximum horizontal principal stress through laboratory tests to measure the rock tensile strength, and maximum the level of hydraulic fracturing through the classical formula of principal stress were analyzed, expecting to find an alternative way to avoid the effects of indoor test system flexibility, improve the maximum horizontal stress testing precision. In this research process, respectively, from the following aspects: the research status at home and abroad of rock tensile test method the strength of carding and comprehensive comparison; indoor double ring direct tensile test and analysis of test results, preliminary study of double ring direct tensile test of the inner diameter of the specimen / straight The diameter, diameter of outer ring / specimen diameter, inner diameter / outer ring diameter optimal range; different size of double ring direct tensile test specimen model numerical simulation study and comparison analysis, indoor test results; indoor test data and field data of the above aspects of the analysis. Based on the preliminary results are as follows: (1) for the same area in different test methods of rock testing rock tensile strength was very different. The direct tensile, bending and stretching, Brazil split, perfect hollow rock column test theory, test guidance system has been mature. The definition of the principle of direct tensile test to the rock tensile the strength of the bending tensile test. The numerical measured is too large, many influencing factors. Brazil split test controversy, there are many factors, but the high degree of approval. The hollow rock column test in recent years the rapid development, test means Conductor system is becoming more and more mature. The double ring direct tensile test of domestic and foreign research is few, the lack of test guidelines system. (2) was tested by double ring direct tensile test design inside and outside the ring diameter of the specimen, the inner diameter and the diameter of the specimens than in 0.32~ 0.47, outer ring diameter ratio in rock 0.53~0.69 and the diameter of the inner diameter and the outer diameter of rock at 0.58~0.69, rock tensile strength values obtained are more reliable. (3) specimens using ABAQUS numerical simulation software of dual ring direct tensile test of 54 different sizes of simulations show that when the outer ring diameter / specimen diameter ratio in the range of 0.53~0.74, the inner diameter / specimen diameter is 0.32~0.48, the stress distribution is relatively uniform test piece, theoretically can obtain the tensile strength of rock is stable and reliable. At the same time to verify the indoor double ring directly The tensile test specimen obtained within the outer ring diameter / specimen diameter ratio range is reasonable. It is important to emphasize that when choosing the diameter / outer ring specimen diameter is larger than the value, the inner diameter / specimen diameter ratio corresponding to selection bias (4) get bigger. In Hebei Yixian County and Shandong Honghe rock laboratory tests were carried out to estimate the maximum horizontal principal stress, and the classical hyduaulic maximum horizontal crack formula of principal stress comparative analysis found: the bending tensile test, splitting test disc (strip method, 2:1), hollow rock column test (1:1 oil) the maximum level of maximum horizontal principal stress is greater than the estimate of the principal stress field of 50% or even more than 100%, seriously too large. While the disc splitting test (pyramid method, 1:1), the direct tensile test, the hollow rock column test (1:1 injection) the maximum horizontal principal stress is slightly larger than the estimated field The maximum horizontal principal stress; the maximum horizontal tworing direct tensile test is slightly less than the actual principal stress, are within the acceptable range. The split test disc (pyramid method, 2:1) to obtain the tensile strength of rock with large discreteness, data is not reliable. The hollow rock column (1:2, water injection test the two comparison results) are not unified, the need for further research.

【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU45
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本文编号：1420637