發(fā)布時間：2018-05-06 14:24

  本文選題：PFC~(2D) + 深埋大理巖�。� 參考：《昆明理工大學》2013年博士論文

【摘要】：21世紀是地下工程向深部發(fā)展的世紀,深埋隧洞、核廢料儲存、深部地熱開發(fā)都涉及到深埋巖體力學問題。20世紀80年代開始,加拿大、瑞典、日本、瑞士、美國等國都建立了地下實驗室,對硬巖高應力破壞的監(jiān)測技術、理論研究和相關數(shù)值分析方面取得了輝煌的成績,其中以加拿大URL對Lac du Bonnet花崗巖的研究最為卓著。 目前對于深埋大理巖力學特性的研究可參照加拿大URL花崗巖的研究思路,主要集中于4個方面：(1)強度特征除了傳統(tǒng)的峰值強度和殘余強度外,人們還提出了描述裂紋狀態(tài)的啟裂強度和損傷強度。對于小尺度巖塊的各種強度閾值可采用試驗手段獲得；大體積巖體的強度閾值只有通過數(shù)值方法獲得,近年來基于PFC的SRM(綜合巖體模型)對此問題富有成效。(2)開挖損傷區(qū)域(EDZ)深埋隧洞開挖后由于應力調(diào)整、爆破擾動、溫度濕度變化等因素會導致開挖面附近形成開挖損傷區(qū)域,了解開挖損傷區(qū)域的范圍、損傷程度和演化特征對評價圍巖穩(wěn)定、滲透擴散規(guī)律和支護措施具有重要意義。(3)革新的試驗技術研究目前真三軸試驗機越來越普及,但硬巖的試驗還要求真三軸加壓時能同時監(jiān)測壓縮過程中的聲發(fā)射、波速變化、滲透率變化,或?qū)Σ煌瑴囟拳h(huán)境的模擬,還應能實現(xiàn)對海量試驗數(shù)據(jù)的高速連續(xù)采集。(4)大型原位試驗設計和實施室內(nèi)試驗針對小尺度的巖塊力學特性開展研究,如果要將相關認識拓展至大尺度巖體還需要設計并開展針對性原位試驗。 本文主要工作致力于深埋大理巖力學特性的室內(nèi)試驗研究和描述方法研究。前者包括大理巖試樣各損傷閾值的測定和峰后力學特性的試驗研究,通過與花崗巖試驗成果的對比,豐富了目前硬巖的研究成果；后者探討大理巖力學特性的PFC方法描述,即用PFC描述了隧洞的開挖損傷特征、巖體強度特征和大理巖峰后特征,拓展了PFC方法在硬巖強度特征與開挖損傷區(qū)域描述方面的應用。在前述研究成果基礎上,利用PFC標定特定巖體質(zhì)量的開挖損傷深度和形態(tài)獲得了巖體級別的顆粒細觀參數(shù),預測了埋深更大洞段的圍巖損傷深度,與常用的連續(xù)方法相比,基于PFC的圍巖損傷深度預測具有較高的精度,對支護設計具有重要價值。 由于錦屏大理巖隨圍壓變化所具有的脆-延-塑性轉(zhuǎn)換特征,決定了它不會出現(xiàn)軟巖里常見的大變形破壞,也不全是純脆性的破壞,因而破損深度不會太深。在圍巖破損的預測過程中包含了隧洞掘進方法的影響和圍巖應力調(diào)整的影響,因此所預測的破損深度基本趨于圍巖所處應力環(huán)境下的最大破損程度,本文應用PFC2D預測的Ⅲ類圍巖破損深度,對支護深度的確定具有較好的指導意義。 本文主要工作及創(chuàng)新點： (1)完成10組深埋大理巖試驗的單軸壓縮室內(nèi)試驗,通過應力-應變曲線確定大理巖的啟裂強度、損傷強度和峰值強度； (2)完成12組深埋大理巖的常規(guī)三軸壓縮試驗,確定大理巖的峰值強度、殘余強度。并通過試驗揭示出大理巖的隨圍壓增高所展示出來的脆-延轉(zhuǎn)換特征,在較高的圍壓水平下,大理巖展現(xiàn)出理想塑性的力學響應； (3)采用基于Hoek-Brown強度的本構(gòu)模型對錦屏Ⅱ類圍巖進行了損傷深度預測,該模型能夠統(tǒng)一描述大理巖在不同圍壓水平下的脆-延-塑性轉(zhuǎn)換特征： (4)采用PFC方法從細觀層面對大理巖的脆-延轉(zhuǎn)換特征進行了描述,研究了基于Bond Particle Model模型的細觀參數(shù)取值規(guī)律； (5)在合理描述大理巖脆-延轉(zhuǎn)換的基礎上,發(fā)展了基于PFC數(shù)值方法的模擬手段對深埋大理巖隧洞的圍巖開挖損傷區(qū)域進行了直接的描述； (6)根據(jù)研究得到的PFC模擬圍巖開挖損傷區(qū)域的數(shù)值方法,對錦屏引水隧洞不同埋深洞段的圍巖開挖損傷深度進行預測,并將預測結(jié)果與現(xiàn)場實測結(jié)果進行了對比； (7)結(jié)合目前深埋地下工程在室內(nèi)實驗、現(xiàn)場試驗、理論研究、數(shù)值分析方法等方面的進展,展望了后續(xù)研究工作。 (8)發(fā)展了運用PFC方法模擬室內(nèi)直剪試驗來反演模型細觀參數(shù)的方法。
[Abstract]:Twenty-first Century is the century of deep development of underground engineering. Deep buried tunnels, nuclear waste storage and deep geothermal development all involve the mechanics of deep buried rock mass in the 80s.20. The underground laboratories in Canada, Sweden, Japan, Switzerland and the United States have established the monitoring techniques, theoretical research and related numerical analysis of hard rock high stress damage. Brilliant achievements have been made, among which URL Lac Du Bonnet granite is the most outstanding one in Canada.
At present, the study of the mechanical properties of deep buried marble can be based on the research ideas of URL granite in Canada. It is mainly concentrated in 4 aspects: (1) besides the traditional peak strength and residual strength, the strength and strength of the crack state are also proposed. The strength threshold of mass rock mass is only obtained by means of numerical method. In recent years, the PFC based SRM (Comprehensive rock mass model) has been successful in this problem. (2) the stress adjustment, blasting disturbance and temperature and humidity changes will lead to the formation of excavation damage near the excavation surface after the excavation of the damaged area (EDZ) deep buried tunnel. It is of great significance to understand the area of the damaged area, the extent of the damage and the evolution characteristics of the damaged area, and it is of great significance to evaluate the stability of the surrounding rock, the law of permeation and diffusion and the support measures. (3) the experimental technology of innovation is becoming more and more popular at present, but the test of hard rock also requires that the sound in the compression process can be monitored at the same time when the three axis is pressurized. Shooting, wave velocity change, permeability change, or simulation of different temperature environments should also be able to achieve high speed and continuous collection of mass test data. (4) large scale in situ test design and implementation of laboratory tests to study the mechanical properties of small scale rock blocks. It is necessary to design and carry out a needle to expand the related knowledge to large scale rock mass. In situ test of sex.
The main work of this paper is to study the experimental research and description method of the mechanical properties of deep buried marble. The former includes the measurement of the damage threshold of marble specimens and the experimental study on the mechanical properties after the peak. By comparing with the results of the granite test, the research results of the hard rock are enriched. The latter discusses the mechanical properties of marble. The PFC method is used to describe the characteristics of tunnel excavation damage, rock strength characteristics and the characteristics of Dali rock peak, which extends the application of the PFC method in the characteristics of hard rock strength and the description of the excavation damage area. On the basis of the previous research results, the excavation damage depth and shape of the specific rock mass are obtained by using PFC to obtain the rock mass. The particle size parameters of the grade predict the damage depth of the surrounding rock in the deeper buried depth. Compared with the common continuous method, the prediction of the damage depth of the surrounding rock based on PFC has a high accuracy and is of great value to the support design.
Because of the brittle ductile transformation characteristics of the Jinping marble with the change of confining pressure, it is determined that it will not appear the common large deformation and failure in the soft rock, not all brittle failure, so the damage depth will not be too deep. The predicted damage depth tends to the maximum damage degree under the stress environment in the surrounding rock. In this paper, the damage depth of type III surrounding rock predicted by PFC2D has a good guiding significance for the determination of the support depth.
The main work and innovation of this article are as follows:
(1) the uniaxial compression indoor tests of 10 groups of deep marble tests were completed, and the crack initiation strength, damage strength and peak strength of marble were determined by stress-strain curves.
(2) to complete the conventional three axis compression test of 12 groups of deep marbles, determine the peak strength and residual strength of marble, and reveal that marble is characterized by brittle ductile transition with high confining pressure, and the marble shows an ideal plastic mechanical response under high confining pressure.
(3) the damage depth of Jinping class II surrounding rock is predicted by the constitutive model based on the strength of Hoek-Brown. The model can describe the brittle ductile transition characteristics of marble under different confining pressure.
(4) the PFC method is used to describe the brittle ductile transition characteristics of marble from the meso layer, and the values of the values of the mesoscopic parameters based on the Bond Particle Model model are studied.
(5) on the basis of a reasonable description of the brittle ductile transition of marble, a numerical method based on PFC is developed to describe the damage area of the surrounding rock excavation in deep marbles.
(6) according to the numerical method of simulating the damage area of surrounding rock excavation by PFC, the damage depth of surrounding rock excavation in different burial tunnels of Jinping diversion tunnel is predicted, and the prediction results are compared with the field measured results.
(7) combined with the progress of laboratory tests, field tests, theoretical studies and numerical analysis methods of deep underground projects, the following research work is prospected.
(8) the method of simulating the indoor direct shear test by PFC method is developed to inverse the microscopic parameters of the model.

【學位授予單位】：昆明理工大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TU45

【參考文獻】

相關期刊論文 前1條

1 賈敏才;王磊;周健;;干砂強夯動力特性的細觀顆粒流分析[J];巖土力學;2009年04期

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本文編號：1852655