本文關(guān)鍵詞：利用巖石抗拉強度估算最大水平主應力的對比分析　出處：《中國地質(zhì)大學(北京)》2017年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 水壓致裂 最大水平主應力 雙圓環(huán)直接拉伸 數(shù)值模擬 對比分析

【摘要】：鉆桿式水壓致裂原地應力測量系統(tǒng)的柔性對最大水平主應力的結(jié)果會產(chǎn)生很大的影響,提高最大水平主應力的測量精度對各種地下工程設計都具有重要意義。嘗試通過室內(nèi)試驗測量巖石抗拉強度值估算最大水平主應力,并與通過經(jīng)典水壓致裂公式計算得到的最大水平主應力進行對比分析,期待找到一種室內(nèi)試驗替代方法避免系統(tǒng)柔性的影響,提高最大水平主應力的測試精度。在這一研究過程中,分別從以下幾個方面展開:梳理了國內(nèi)外巖石抗拉強度試驗方法的研究現(xiàn)狀及綜合對比;進行室內(nèi)雙圓環(huán)直接拉伸試驗并分析試驗結(jié)果,初步探究雙圓環(huán)直接拉伸試驗的內(nèi)環(huán)直徑/試件直徑、外環(huán)直徑/試件直徑、內(nèi)環(huán)直徑/外環(huán)直徑的最優(yōu)比范圍;對雙圓環(huán)直接拉伸試驗的不同尺寸的試件模型進行數(shù)值模擬研究及對比分析,驗證室內(nèi)試驗結(jié)果;室內(nèi)試驗數(shù)據(jù)與現(xiàn)場實測數(shù)據(jù)的對比分析。基于以上幾個方面的研究,初步成果如下:(1)對于同一地區(qū)巖石不同的測試方法測得的巖石抗拉強度值差別很大。直接拉伸、彎曲拉伸、巴西劈裂,空心巖柱等試驗理論完善,試驗指導體系已經(jīng)趨于成熟。其中直接拉伸試驗的原理最接近巖石抗拉強度的定義。彎曲拉伸試驗測得的數(shù)值偏大,影響因素多。巴西劈裂試驗爭論較大,影響因素頗多,但認可度高�？招膸r柱試驗近幾年發(fā)展迅猛,試驗指導體系日漸成熟。雙圓環(huán)直接拉伸試驗國內(nèi)外研究頗少,缺乏系統(tǒng)的試驗指導方案。(2)通過設計部分內(nèi)外環(huán)直徑的雙圓環(huán)直接拉伸試驗的試件進行室內(nèi)試驗,得出內(nèi)環(huán)直徑與試件直徑比處于0.32~0.47,巖石外環(huán)直徑與試件直徑比處于0.53~0.69,巖石內(nèi)環(huán)直徑與外環(huán)直徑比處于0.58~0.69時,獲得的巖石抗拉強度值比較穩(wěn)定可靠。(3)運用ABAQUS數(shù)值模擬軟件對54個不同尺寸的雙圓環(huán)直接拉伸試驗的試樣進行模擬發(fā)現(xiàn):當外環(huán)直徑/試件直徑比的范圍為0.53~0.74,內(nèi)環(huán)直徑/試件直徑比0.32~0.48時,試件的應力分布狀態(tài)比較均勻,理論上來說可以獲得穩(wěn)定可靠的巖石抗拉強度。同時驗證了室內(nèi)雙圓環(huán)直接拉伸試驗初步得到的試件內(nèi)、外環(huán)直徑/試件直徑比范圍的合理性。需要著重強調(diào)的是,當選擇的外環(huán)直徑/試件直徑比數(shù)值偏大時,內(nèi)環(huán)直徑/試件直徑的比也要對應的選擇偏大一些。(4)對河北易縣和山東紅河兩地獲得的巖石進行室內(nèi)試驗估算最大水平主應力,與經(jīng)典水壓致裂公式計算得到的最大水平主應力對比分析發(fā)現(xiàn):通過彎曲拉伸試驗、圓盤劈裂試驗(墊條法,2:1)、空心巖柱試驗(1:1,注油)估算的最大水平主應力均大于現(xiàn)場實測的最大水平主應力50%甚至是100%以上,嚴重偏大。而圓盤劈裂試驗(角錐法,1:1)、直接拉伸試驗、空心巖柱試驗(1:1,注水)估算的最大水平主應力略大于現(xiàn)場實測的最大水平主應力;雙圓環(huán)直接拉伸試驗略小于現(xiàn)場實測的最大水平主應力,都在可接受的范圍內(nèi)。圓盤劈裂試驗(角錐法,2:1)獲得的巖石抗拉強度離散性大,數(shù)據(jù)不穩(wěn)定可靠�？招膸r柱試驗(1:2,注水)兩地的對比結(jié)果不統(tǒng)一,需要進一步研究。
[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.

【學位授予單位】：中國地質(zhì)大學(北京)
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU45
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本文編號：1420637