發(fā)布時(shí)間：2018-05-04 01:17

  本文選題：預(yù)制裂隙 + 巖石力學(xué)性質(zhì)　； 參考：《華僑大學(xué)》2017年碩士論文

【摘要】：水利水電、鐵路、地?zé)衢_采、石油天然氣等工程施工過(guò)程中會(huì)遇到復(fù)雜的工程介質(zhì)——節(jié)理裂隙巖體。天然巖體內(nèi)部不同尺度裂隙相互貫穿、縱橫交錯(cuò),極大地影響了巖體自身的力學(xué)特性,使得強(qiáng)度、彈模以及泊松比等基本力學(xué)參數(shù)產(chǎn)生差異,這些差異與巖體變形過(guò)程當(dāng)中內(nèi)部裂紋發(fā)育的變化規(guī)律相一致。本文以五類裂隙花崗巖試件在0、5、10 MPa圍壓條件下進(jìn)行壓縮試驗(yàn),研究裂隙和圍壓對(duì)巖石的宏觀力學(xué)性質(zhì)及破壞模式的影響;最后,通過(guò)顆粒流PFC2D軟件,采用自主編制的預(yù)制裂隙雙軸壓縮程序?qū)�花崗巖進(jìn)行裂隙和不同圍壓條件下數(shù)值模擬。模擬得到的結(jié)果與室內(nèi)試驗(yàn)結(jié)果對(duì)比,在驗(yàn)證數(shù)值模型可靠的基礎(chǔ)上,獲取試樣受荷載過(guò)程中內(nèi)部細(xì)觀參量,為研究裂隙花崗巖宏觀力學(xué)特性的細(xì)觀機(jī)理提供條件。論文主要的研究成果如下:同等圍壓條件下,隨著裂隙數(shù)目增多,花崗巖樣峰值強(qiáng)度和彈性模量降低;同類型裂紋巖樣,隨著圍壓的增大,花崗巖巖樣的峰值強(qiáng)度、彈性模量、峰值軸向應(yīng)變和峰值環(huán)向應(yīng)變?cè)龃?完整巖樣應(yīng)力達(dá)到峰值強(qiáng)度后應(yīng)力迅速跌落,應(yīng)力應(yīng)變曲線峰值處呈現(xiàn)倒“V”型,含預(yù)制裂隙花崗巖樣應(yīng)力達(dá)到峰值強(qiáng)度后曲線呈現(xiàn)緩慢跌落;完整巖樣在單軸壓縮條件下呈現(xiàn)劈裂貫通破壞,單軸壓縮條件下含裂隙巖樣裂紋首先在裂隙內(nèi)部尖端萌生再沿著軸向擴(kuò)展形成劈裂貫通破壞,而三軸壓縮條件下含裂隙巖樣呈現(xiàn)拉剪混合式破壞。借助PFC2D數(shù)值模擬軟件,分析單軸、三軸加載過(guò)程中裂紋擴(kuò)展規(guī)律,并從細(xì)觀機(jī)制上解釋圍壓和裂隙對(duì)宏觀力學(xué)參數(shù)影響。本次研究宏細(xì)觀結(jié)合,互為補(bǔ)充印證。
[Abstract]:Water conservancy and hydropower, railway, geothermal exploitation, oil and gas engineering will encounter complex engineering mediums-jointed fractured rock mass. The fractures of different scales in natural rock mass run through each other and crisscross, which greatly affects the mechanical properties of rock mass itself, and makes the basic mechanical parameters such as strength, modulus of elasticity and Poisson's ratio different. These differences are consistent with the law of internal crack development during rock deformation. In this paper, five types of fractured granite specimens are tested under the confining pressure of 0 ~ 5 ~ 10 MPa to study the influence of fracture and confining pressure on the macroscopic mechanical properties and failure mode of rock. Finally, by means of PFC2D software of particle flow, The prefabricated fracture biaxial compression program is used to simulate the granite fracture and different confining pressure. The simulation results are compared with the results of laboratory tests. On the basis of verifying the reliability of the numerical model, the internal meso-parameters during the loading process of the specimens are obtained, which provides the conditions for the study of the meso-mechanism of the macroscopic mechanical properties of the fissured granite. The main research results are as follows: under the same confining pressure, the peak strength and elastic modulus of granite samples decrease with the increase of the number of fissures, the peak strength and elastic modulus of granite samples with the increase of confining pressure, the peak strength and elastic modulus of granite samples decrease with the increase of confining pressure. The peak axial strain and the peak circumferential strain increase, the stress of intact rock sample rapidly falls after reaching the peak strength, and the peak value of stress-strain curve shows the inverted "V" type. The curves of granite samples with prefabricated fractures show a slow drop after the stress reaches the peak strength, and the intact rock samples show splitting through failure under uniaxial compression. Under uniaxial compression conditions, cracks of fractured rock samples first germinate at the tip of fractures and then propagate along the axial direction to form splitting through failure, while under triaxial compression conditions, fracture rock samples show tensile and shear failure. By means of PFC2D numerical simulation software, the law of crack growth during uniaxial and triaxial loading is analyzed, and the influence of confining pressure and fracture on macroscopic mechanical parameters is explained from the mesoscopic mechanism. This study combines macro-and-meso-view and is complementary to each other.
【學(xué)位授予單位】：華僑大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TU45

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