本文選題：滾石 + 碰撞破裂機(jī)理��； 參考：《浙江大學(xué)》2017年碩士論文

【摘要】：作為一種特殊的地質(zhì)災(zāi)害,滾石災(zāi)害雖然規(guī)模較小,但是因其具有較大的突發(fā)性和不確定性,已經(jīng)對(duì)國民經(jīng)濟(jì)和人民生命財(cái)產(chǎn)造成了巨大危害。開展?jié)L石坡面碰撞研究對(duì)探究滾石坡面碰撞機(jī)理,分析滾石坡面碰撞破裂效應(yīng)進(jìn)而修正坡面碰撞模型有重大的意義。本文通過系統(tǒng)的坡面碰撞試驗(yàn)和數(shù)值模擬分析,探究了碰撞速度、滾石力學(xué)性質(zhì)、碰撞角度和滾石尺寸對(duì)滾石碰撞破裂特征的影響,分析了滾石碰撞破裂條件下碰撞恢復(fù)系數(shù)的變化規(guī)律,主要內(nèi)容和基本認(rèn)識(shí)如下:(1)在文獻(xiàn)調(diào)查的基礎(chǔ)上,分析比較了各種巖石試樣預(yù)損傷方法的優(yōu)劣,提出高溫加熱的方法制備巖石試樣,并通過一系列試驗(yàn)檢驗(yàn)了高溫?fù)p傷效果。試驗(yàn)表明:高溫加熱將導(dǎo)致花崗巖試樣質(zhì)量略微減小并產(chǎn)生不可逆的體積膨脹�；◢弾r的單軸抗壓強(qiáng)度、劈裂抗拉強(qiáng)度、彈性模量和縱波波速均隨溫度的升高而降低。一般在400℃以內(nèi),溫度的影響較小;隨著溫度的升高,巖石性質(zhì)損傷劣化程度加劇。綜合比較各種力學(xué)參數(shù),采用基于縱波波速的巖石完整性指標(biāo)作為巖石試樣損傷指標(biāo)效果較好。(2)在自主研制的滾石碰撞系統(tǒng)上對(duì)不同特征的滾石試樣進(jìn)行一系列室內(nèi)碰撞試驗(yàn),詳細(xì)分析了滾石力學(xué)性質(zhì)、碰撞速度、入射角度和尺寸大小等因素耦合作用下的滾石坡面碰撞破裂機(jī)理,探討了碰撞破裂對(duì)滾石運(yùn)動(dòng)特征的影響。結(jié)果表明:滾石力學(xué)性質(zhì)和碰撞速度是控制滾石碰撞破裂的主要因素,滾石力學(xué)性質(zhì)越差,碰撞速度越大,滾石碰撞越破碎。滾石破裂存在法向速度閾值,隨著力學(xué)性質(zhì)的劣化,破裂法向速度閾值減小。碰撞入射角對(duì)滾石碰撞破裂及能量恢復(fù)系數(shù)影響較大;碰撞破裂不但會(huì)引起滾石總的能量恢復(fù)系數(shù)減小,而且會(huì)造成個(gè)別碎塊具有較大速度。(3)采用三維動(dòng)力有限元軟件LS-DYNA,對(duì)滾石坡面碰撞過程進(jìn)行數(shù)值模擬分析,基于試驗(yàn)獲得的滾石坡面碰撞破裂特征和結(jié)果,對(duì)數(shù)值模型及其參數(shù)進(jìn)行調(diào)整與校驗(yàn),結(jié)果表明:采用參數(shù)優(yōu)化后的土/混凝土模型,可以較好的反映滾石碰撞破裂特征。滾石的抗拉強(qiáng)度對(duì)破裂特征影響較大,而坡面的結(jié)構(gòu)形式、邊界條件以及力學(xué)參數(shù)對(duì)滾石碰撞恢復(fù)系數(shù)有較大的影響。在此基礎(chǔ)上,采用理想剛體坡面模型,進(jìn)一步擴(kuò)大了碰撞速度、滾石尺寸和力學(xué)性質(zhì)等參數(shù)變化范圍,研究了碰撞破裂對(duì)滾石運(yùn)動(dòng)特征的影響。數(shù)值模擬結(jié)果表明:滾石力學(xué)性質(zhì)越差,滾石碰撞能量恢復(fù)系數(shù)越小;破裂前,碰撞恢復(fù)系數(shù)隨碰撞速度的增大而略有減小,滾石碰撞破裂后,能量恢復(fù)系數(shù)急劇減小,碰撞速度大于某一值后,能量恢復(fù)系數(shù)平緩下降。
[Abstract]:As a special geological disaster, the rolling stone disaster, though small in scale, has caused great harm to the national economy and people's life and property because of its large unexpected and uncertainty. The research on the collision of rolling stone slope to explore the mechanism of the collision of rolling stone slope, analyze the impact and rupture effect of the rolling stone slope and then amend the slope surface The collision model is of great significance. In this paper, the impact velocity, the mechanical properties of the rolling stone, the impact angle and the rolling stone size have been investigated through the systematic slope impact test and numerical simulation analysis. The change law of the collision recovery coefficient under the conditions of the rolling stone collision and fracture is analyzed. The main contents and basic understanding are as follows. (1) (1) on the basis of the literature survey, the advantages and disadvantages of the pre damage methods of various rock samples were compared and compared, and the high temperature heating method was put forward to prepare the rock samples, and a series of tests were made to test the effect of high temperature damage. The uniaxial compressive strength, splitting tensile strength, modulus of elasticity and longitudinal wave velocity of the rock decreased with the increase of temperature. The temperature was less influenced by the temperature at 400 degrees C. With the increase of temperature, the deterioration degree of the rock properties was aggravated. The rock integrity index based on the longitudinal wave velocity was used as rock test. (2) a series of indoor collision tests are carried out on the rolling stones with different characteristics on the independently developed rolling stone collision system. The mechanism of the rolling stone collision and fracture mechanism under the coupling effect of the mechanical properties of the rolling stones, the velocity of the collision, the angle of incidence and the size of the rolling stones is analyzed in detail, and the collision rupture to the rolling stone is discussed. The results show that the mechanical properties of the rolling stones and the velocity of collision are the main factors to control the collision and rupture of the rolling stones. The worse the mechanical properties of the rolling stones, the greater the collision speed, the more crushing of the rolling stones. The fracture of the rolling stones has a normal velocity threshold, with the deterioration of the mechanical properties, the breaking method is reduced to the velocity threshold. The collision incidence angle has the impact on the rolling stone. The impact fracture and the energy recovery coefficient have great influence, and the collision rupture not only causes the reduction of the total energy recovery coefficient of the rolling stones, but also causes a large speed of the individual fragments. (3) the three-dimensional dynamic finite element software LS-DYNA is used to analyze the process of the rolling stone slope collision, and the fracture of the rolling rock slope based on the test is special. The results show that the numerical model and its parameters are adjusted and checked. The results show that the parameters optimized by the soil / concrete model can better reflect the fracture characteristics of the rolling stones. The tensile strength of the rolling stones has a great influence on the fracture characteristics, and the structural form of the slope, boundary conditions and the mechanical parameters have the coefficient of recovery of the rolling stone collision. On this basis, using the ideal rigid body slope model, the impact velocity, the rolling stone size and the mechanical properties are further expanded, and the impact of the collision rupture on the rolling stone motion characteristics is studied. The numerical simulation results show that the worse the mechanical properties of the rolling stones, the smaller the energy recovery coefficient of the rolling stone collision, and the collision before the collision. The recovery coefficient decreases slightly with the increase of the collision speed. After the rolling stone collision, the energy recovery coefficient decreases sharply. After the collision speed is greater than a certain value, the energy recovery coefficient decreases slowly.
【學(xué)位授予單位】：浙江大學(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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