本文選題：散粒體斜坡 + 單顆粒�。� 參考：《成都理工大學(xué)》2015年碩士論文

【摘要】：散粒體斜坡又稱溜砂坡,在我國西南和西北部的一些地區(qū)區(qū)域性的分布,通常由碎石、礫石和砂組成,呈散體結(jié)構(gòu),幾乎沒有細(xì)粒和其他膠結(jié)物連接,呈現(xiàn)出“一盤散沙”的狀態(tài)。散粒體斜坡通常對外界擾動非常的敏感,因此頻繁活動,對沿線的線性交通的安全運(yùn)行造成危害,同時(shí)由于散粒體變形破壞有明顯的突發(fā)性,因此對人身和財(cái)產(chǎn)安全造成很大的威脅。散粒體斜坡變形破壞的研究起步較晚,前人的研究主要集中在散粒體堆積體的非線性動力學(xué)方面,通過沙堆試驗(yàn)或者單面坡試驗(yàn)等物理試驗(yàn)?zāi)M,認(rèn)為散粒體邊坡是一個(gè)典型的多元廣延空間自由度的耗散動力學(xué)系統(tǒng),符合自組織臨界性原理,當(dāng)坡面上一點(diǎn)失穩(wěn)就可能會波及周圍其他臨近區(qū)域,導(dǎo)致坡面大面積的散粒體物質(zhì)失穩(wěn),并且散粒體的自組織臨界性受到規(guī)模和級配的影響。由于這種自組織臨界性,散粒體斜坡在臨界狀態(tài)下受到擾動時(shí)出現(xiàn)的破壞形式和規(guī)模不可預(yù)知。本文認(rèn)為散粒體斜坡既有表面單個(gè)顆粒或者多個(gè)顆粒的運(yùn)動,也有大規(guī)模的整體失穩(wěn),在廣泛收集國內(nèi)外有關(guān)散粒體文獻(xiàn)資料和大量現(xiàn)場第一手資料的基礎(chǔ)上,采用理論推導(dǎo)和物理模擬試驗(yàn)的手段,從地質(zhì)災(zāi)害學(xué)的角度對其進(jìn)行探索研究。主要內(nèi)容包括:(1)通過野外調(diào)查并取樣篩分,分析散粒體斜坡的分布特征、物質(zhì)組成、形成條件和影響因素。(2)分析散粒體顆粒之間的接觸作用,通過直剪實(shí)驗(yàn)的方法研究顆粒的抗剪強(qiáng)度特征,分析說明顆粒粒徑以及級配對抗剪強(qiáng)度的影響。(3)劃分了散粒體斜坡的活動階段,闡明散粒體斜坡表層顆粒的運(yùn)動破壞形式。分析了表層單顆粒起動的力學(xué)判據(jù),通過實(shí)驗(yàn)的方法驗(yàn)證了單顆粒起動判據(jù)的實(shí)用性,與實(shí)驗(yàn)值非常吻合,即表層單個(gè)規(guī)則顆粒起動與顆粒本身的重量無關(guān),只要幾何特征滿足顆粒即可起動;并且散粒體單顆粒的啟動判據(jù)能很好的解釋散粒體斜坡的分選性。研究表明顆粒形狀對顆粒起動條件有較大的影響。(4)通過物理模擬整體變形破壞機(jī)制,并提出三種散粒體邊坡變形破壞模式即表面顆粒滑流,蠕滑剪出破壞和潰散破壞。(5)對散粒體斜坡的穩(wěn)定性評價(jià)進(jìn)行進(jìn)一步研究。在散粒體斜坡的穩(wěn)定性評價(jià)方法方面,結(jié)合物理模擬實(shí)驗(yàn),針對破壞模式,有針對性提出穩(wěn)定性判別方法。針對表面顆粒滑流破壞模式提出關(guān)鍵顆粒的判別方法;針對蠕滑整體剪出破壞模式,提出采用傳統(tǒng)的畢肖普條分法。
[Abstract]:A regional distribution in some parts of the southwest and northwest of China, usually composed of gravel, gravel, and sand, with a granular structure and almost no fine grain and other cementation. It presents a state of "scattered sand". Granular slopes are usually very sensitive to external disturbances, so frequent activities are harmful to the safe operation of linear traffic along the route. At the same time, there are obvious sudden damage due to the deformation and failure of granular bodies. Therefore, it poses a great threat to the security of person and property. The research on the deformation and failure of granular slope started relatively late. The previous studies mainly focused on the nonlinear dynamics of granular accumulations, and simulated by physical tests such as sand pile test or single slope test. It is considered that the granular slope is a typical dissipative dynamic system with multiple and extensive spatial degrees of freedom, which accords with the principle of self-organizing criticality. When a single point of instability on the slope surface is unstable, it may spread to other adjacent areas around the slope. It leads to the instability of large area of granular matter on the slope and the influence of size and gradation on the self-organizing criticality of the granular body. Due to this self-organized criticality, the failure form and scale of the granular slope are unpredictable when disturbed under the critical state. In this paper, it is considered that there are not only the movement of single or multiple particles on the surface of the granular slope, but also the mass instability of the whole body. On the basis of the extensive collection of domestic and foreign literature on the granular body and a large number of firsthand data on the spot, By means of theoretical derivation and physical simulation test, the geological hazard is studied from the point of view of geological hazard. The main contents include: (1) through field investigation and sampling and screening, the distribution characteristics, material composition, formation conditions and influencing factors of the granular slope are analyzed) and the contact between the granular particles is analyzed. By means of direct shear experiment, the characteristics of shear strength of particles are studied, and the effects of particle size and gradation on shear strength are analyzed. The active stages of granular slopes are divided, and the motion and failure modes of particles in the surface layer of granular slopes are clarified. The mechanical criterion of single particle starting is analyzed. The practicability of single particle starting criterion is verified by the experimental method, which is in good agreement with the experimental value, that is, the starting of a single regular particle in the surface layer is independent of the weight of the particle itself. The starting criterion of single particle can explain the separation of granular slope well. The results show that particle shape has a great influence on the starting condition of particles. (4) physical simulation of the whole deformation and failure mechanism is carried out, and three kinds of deformation and failure modes of granular slope, i.e. surface particle slip flow, are proposed. The stability evaluation of granular slope is further studied. In the aspect of stability evaluation method of granular slope, combined with physical simulation experiment, a method of judging stability is put forward according to the failure mode. According to the failure mode of surface particle sliding flow, the method of distinguishing key particles is proposed, and the traditional Bishop strip method is proposed for the failure mode of creep whole shearing.
【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】：TU43

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本文編號：1800296