本文選題：裂隙巖體 + 裂紋貫通模式　； 參考：《成都理工大學(xué)》2015年碩士論文

【摘要】：自然巖體是一種非連續(xù)介質(zhì)體,其內(nèi)部充斥著大量裂隙、空隙等缺陷,使巖體力學(xué)性質(zhì)呈現(xiàn)明顯的各向異性。節(jié)理、裂隙在外載下的擴展、貫通對巖體的力學(xué)特性產(chǎn)生顯著的影響,也是導(dǎo)致巖體發(fā)生局部化破壞的主要原因。因此,對裂隙巖體力學(xué)性質(zhì)和變形破壞化過程的正確分析具有十分重要的工程意義。從能量觀點可知,巖體的破壞本質(zhì)上是能量耗散和釋放的結(jié)果,從能量角度研究巖體變形破壞的力學(xué)相應(yīng)特點及本質(zhì)特征,能較真實的反映巖體的破壞規(guī)律。本文通過相似材料模擬玄武巖等脆性材料,制作不同裂隙傾角及長度的單裂隙試樣和不同空間分布的雙裂隙試樣。以PIV粒子高速成像測速技術(shù)方法作為試驗觀測手段,采用自主研發(fā)“YY-L600型”雙軸壓縮試驗系統(tǒng)進行雙軸循環(huán)壓縮試驗。分析了裂隙試樣的力學(xué)性質(zhì)、變形破壞過程及裂紋貫通模式。從能量觀點,研究了在加載過程中裂隙試樣的能量演化規(guī)律、能耗特征及損傷特性。主要成果如下:(1)預(yù)制裂隙對試件的力學(xué)及強度特性影響明顯,同等加載條件下,完整試樣的峰值強度明顯高于含裂隙試樣的峰值強度。起始循環(huán)值、圍壓及裂隙的組合形式對試樣的軸向應(yīng)力-應(yīng)變曲線的整體形態(tài)影響較小,但是會影響試樣的峰值強度、起裂強度/峰值強度的比值;(2)預(yù)制單裂隙和雙裂隙試件破壞過程大致經(jīng)歷四個階段:初始壓密階段,彈性變形階段,次生裂紋萌生和擴展,預(yù)制裂隙四周次生裂紋加速擴展,試件整體失穩(wěn)破壞。雙裂隙試件與單裂隙試件比較,起裂的時間早,大規(guī)模的裂紋貫通時間較單裂隙試件早,峰值強度低于單裂隙試件;(3)單裂隙裂紋和雙裂隙裂紋在擴展過程中都產(chǎn)生翼裂紋,準(zhǔn)共面次生裂紋及傾斜次生裂紋,但單裂隙裂紋在預(yù)制裂隙中間產(chǎn)生豎直的傾斜次生裂紋,這是雙裂隙試件所不具有的,雙裂隙裂紋在上下預(yù)制裂隙中間巖橋區(qū)域剪切裂紋的形式貫通,并沒有以豎向張拉裂紋貫通,這主要原因是裂隙間間距較小,應(yīng)力集中效應(yīng)使得巖橋沒有形成豎向張拉裂紋;(4)依據(jù)斷裂力學(xué)裂紋的不同形式和裂隙擴展破壞過程,可以將單雙裂隙試樣在雙軸循環(huán)加載條件下裂紋擴展模式分為張性貫通、張剪復(fù)合貫通和剪性貫通三大類,根據(jù)最終貫通裂紋類型不同,每個大類又可細分為若干亞類。對應(yīng)于裂紋擴展貫通模式,可將試樣的破壞模式分為三類,既張拉破壞模型、剪切破壞模型及張剪復(fù)合破壞模型;(5)單裂隙試件和雙裂隙試件,在循環(huán)加載過程,能量演化都呈現(xiàn)非線性增長趨勢,能量在變形破壞過程的各階段呈現(xiàn)不同的轉(zhuǎn)化形式。試件能量耗散特性的影響因素主要有裂隙長度、裂隙傾角、巖橋長度、裂隙組合方式及加載圍壓五個方面;(6)不同幾何尺寸及組合的裂隙試件,其極限儲能不同。在同一圍壓條件下,試樣的極限儲能起始循環(huán)值的相關(guān)性不明顯,而裂隙傾角及裂隙長度對試樣的極限儲能有較大的影響。試樣的極限儲能與其抗壓強度具有較好的相關(guān)性,抗壓強度越高,試件在破壞前儲存的可釋放應(yīng)變能越大,既隨著抗壓強度的增大,試件的極限儲能儲能越大;(7)試件不同變形階段對應(yīng)不同的能量演化規(guī)律。從破壞形式上來看,試件破壞形態(tài)與峰后能量集中釋放程度有較好的對應(yīng)性。從破壞形態(tài)上來看,峰前耗散能量越多,巖石內(nèi)部擴展發(fā)育的裂紋越多,試件破壞后巖塊越小,破碎度越高,既裂隙試件破碎程度:張剪復(fù)合破壞試件最大,剪切破壞試件次之,張拉破壞試件最小;(8)單裂隙試件和雙裂隙試件其損傷變量與軸向應(yīng)力曲線都呈非線性關(guān)系,且各個試件都具有相似的曲線形式,隨著應(yīng)力的不斷增大,試件的損傷變量不斷增大。損傷變量D與軸向之間的關(guān)系可以表達為:。
[Abstract]:Natural rock mass is a discontinuous medium, which is filled with a large number of cracks and gaps, which makes the mechanical properties of rock mass apparent anisotropy. Joints and cracks are extended under the external load. Penetration has a significant influence on the mechanical properties of rock mass, which is also the main cause of rock mass destruction. The correct analysis of the mechanical properties of body and the process of deformation and destruction is of great engineering significance. From the point of view of energy, the destruction of rock mass is the result of energy dissipation and release. The mechanical characteristics and essential characteristics of rock mass deformation and failure are studied from the angle of energy. It can reflect the failure law of rock mass more truly. The similar material simulated the brittle materials such as basalt, and made the single fracture specimens with different fracture angles and lengths and the double fracture specimens with different spatial distribution. The double axis cyclic compression test was carried out by the self developed "YY-L600" biaxial compression test system by the PIV particle high-speed imaging velocity measurement technique. The mechanical properties of the fractured specimen, the deformation and failure process and the crack penetration mode. From the energy point of view, the energy evolution law, the energy consumption characteristics and the damage characteristics during the loading process are studied. The main results are as follows: (1) the prefabricated fissure has an obvious effect on the mechanical and strength characteristics of the specimen, and the peak strength of the complete specimen under the same loading condition. The initial cycle value, the confining pressure and the combination of cracks have little influence on the overall shape of the axial stress strain curve of the specimen, but it will affect the peak strength of the specimen, the ratio of the cracking strength / peak strength, and (2) the failure process of the prefabricated single and double fracture specimens is roughly four orders. Section: initial compaction stage, elastic deformation stage, secondary crack initiation and expansion, accelerated propagation of secondary cracks around prefabricated cracks, overall instability and failure of specimens. Compared with single fracture specimens, double fissure specimen and single crack specimen are earlier than single fissure specimens, and peak strength is lower than single fissure test; (3) single fissure cracking. Cracks of wings, quasi coplanar secondary cracks and inclined secondary cracks occur during the propagation process, but single crack cracks produce vertical inclined secondary cracks in the middle of the prefabricated fissures, which are not found in the double fracture specimens. The double crack cracks are connected in the form of the shear crack in the middle rock bridge area in the upper and lower precast cracks. The main reason is that the vertical tensile crack is through, the main reason is that the gap between cracks is small, the stress concentration effect makes the rock bridge not forming the vertical tensile crack. (4) according to the different forms of fracture mechanics and crack propagation, the crack propagation mode can be divided into tensioning through the double axis cyclic loading condition. There are three major categories of shear combined penetration and shear penetration. According to the types of final through through cracks, each large class can be subdivided into several subclasses. Corresponding to the mode of crack propagation through, the failure modes of the specimen can be divided into three categories: tensile failure model, shear failure model and Zhang Jianfu's combined failure model; (5) single fracture specimen and double fracture specimen, In the cyclic loading process, the energy evolution shows a nonlinear growth trend, and the energy is different in various stages of the deformation and failure process. The influence factors of the energy dissipation characteristics are five aspects: fracture length, fracture angle, rock bridge length, fracture combination and loading confining pressure; (6) different geometrical sizes and combinations The limit storage energy is different. Under the same confining pressure, the correlation of the initial cycle value of the ultimate energy storage of the specimen is not obvious, and the fracture angle and the length of the crack have great influence on the limit energy storage of the specimen. The ultimate energy storage of the specimen has a good correlation with the compressive strength, the higher the compressive strength, the storage of the specimen before the damage. The greater the release strain energy is, the higher the compressive strength is, the greater the energy storage energy of the specimen is, and (7) the different deformation stages of the specimen correspond to the different energy evolution laws. From the form of failure, the damage form and the concentration of energy concentration after the peak are better. The more cracks developed in the rock, the smaller the rock mass, the smaller the rock mass, the higher the fracture degree, the fracture degree of the fracture specimen, the maximum of the fracture specimen, the shear failure test, the minimum tensile failure test, and (8) the nonlinear relationship between the damage variable and the axial stress curve of the single fracture and the double fracture specimens. All the specimens have similar curvilinear form. As the stress increases, the damage variable of the specimen increases continuously. The relationship between the damage variable D and the axial direction can be expressed as:.
【學(xué)位授予單位】：成都理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU45

【參考文獻】

相關(guān)期刊論文 前5條

1 許江,大久保誠介,鮮學(xué)福;循環(huán)載荷對三城目安山巖變形特性的影響[J];重慶大學(xué)學(xué)報(自然科學(xué)版);2000年06期

2 陳旭光;張強勇;;巖石剪切破壞過程的能量耗散和釋放研究[J];采礦與安全工程學(xué)報;2010年02期

3 孫衛(wèi)軍;周維垣;;裂隙巖體彈塑性-損傷本構(gòu)模型[J];巖石力學(xué)與工程學(xué)報;1990年02期

4 許江;楊紅偉;李樹春;姜永東;;循環(huán)加、卸載孔隙水壓力對砂巖變形特性影響實驗研究[J];巖石力學(xué)與工程學(xué)報;2009年05期

5 葛修潤;周期荷載下巖石大型三軸試件的變形和強度特性研究[J];巖土力學(xué);1987年02期

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