【摘要】：邊坡工程的穩(wěn)定性是土木行業(yè)一直以來比較關(guān)注的問題，目前常用連續(xù)介質(zhì)力學(xué)的方法對(duì)邊坡穩(wěn)定性進(jìn)行分析，但這些方法都無法考慮邊坡內(nèi)部缺陷對(duì)邊坡穩(wěn)定性的影響。斷裂力學(xué)的研究對(duì)象是帶有宏觀裂縫的結(jié)構(gòu)體，而實(shí)際的邊坡正是這種結(jié)構(gòu)體，因此可以用斷裂力學(xué)原理分析邊坡的穩(wěn)定性。本文主要針對(duì)兩種不同的破壞模式對(duì)邊坡的穩(wěn)定性進(jìn)行分析。 對(duì)于普通均質(zhì)粘土邊坡，假設(shè)其破壞是由坡頂開裂引起的，邊坡穩(wěn)定性的判據(jù)是坡頂裂縫長(zhǎng)度是否達(dá)到臨界縫長(zhǎng)。主要研究?jī)?nèi)容及結(jié)論為： ①運(yùn)用有限元軟件，根據(jù)邊坡坡頂不同位置的應(yīng)力強(qiáng)度因子分布確定邊坡最易開裂位置；再確定臨界縫長(zhǎng)；在最易開裂位置設(shè)置大于臨界縫長(zhǎng)的裂縫，按計(jì)算的裂縫擴(kuò)展角依次往下擴(kuò)展，直至裂縫貫通，所得破裂面即為基于斷裂力學(xué)的邊坡最危險(xiǎn)滑動(dòng)面。根據(jù)裂縫擴(kuò)展時(shí)Ⅰ、Ⅱ型應(yīng)力強(qiáng)度因子的比值判斷邊坡破壞類型為Ⅰ-Ⅱ復(fù)合型，但是更加趨近于Ⅰ型破壞。 ②將基于斷裂力學(xué)和傳統(tǒng)極限平衡法求得的最危險(xiǎn)滑動(dòng)面對(duì)比，，表明運(yùn)用斷裂力學(xué)原理研究粘土邊坡穩(wěn)定性是可行的。 ③運(yùn)用有限元軟件，研究邊坡高度及傾角對(duì)邊坡斷裂破壞的影響。得到坡頂最易開裂位置與坡緣距離隨著邊坡高度或傾角的增加而增加；臨界縫長(zhǎng)隨著邊坡高度或傾角的增加而減��；隨著邊坡高度或傾角增加，邊坡更加趨近于Ⅰ型破壞。 對(duì)于內(nèi)部含有共線缺陷裂縫或由層狀巖體構(gòu)成的邊坡，將其缺陷簡(jiǎn)化為內(nèi)部的一組共線裂縫，假設(shè)邊坡破壞是由這組共線裂縫擴(kuò)展導(dǎo)致的。邊坡穩(wěn)定性的判據(jù)是裂縫尖端等效應(yīng)力強(qiáng)度因子是否小于斷裂韌度。主要研究?jī)?nèi)容及結(jié)論為： ①當(dāng)邊坡內(nèi)部存在缺陷裂縫時(shí)，裂縫部位巖土體的抗滑力不計(jì)。運(yùn)用有限元軟件，假設(shè)不同長(zhǎng)度及間距的共線裂縫，求解其應(yīng)力強(qiáng)度因子，研究裂縫條數(shù)、長(zhǎng)度及間距不同時(shí)，裂縫尖端應(yīng)力強(qiáng)度因子的變化規(guī)律。 ②將基于斷裂力學(xué)求得的邊坡等效安全系數(shù)和極限平衡法求得的安全系數(shù)對(duì)比，表明基于斷裂力學(xué)求解邊坡等效安全系數(shù)的可行性。 ③將兩種邊坡破壞模式進(jìn)行對(duì)比，研究其區(qū)別與聯(lián)系。
[Abstract]:The stability of slope engineering is always concerned by civil engineering. At present, the method of continuum mechanics is used to analyze the stability of slope, but none of these methods can take into account the influence of internal defects of slope on slope stability. The research object of fracture mechanics is the structural body with macroscopic cracks, and the actual slope is this kind of structure, so the stability of slope can be analyzed by the principle of fracture mechanics. In this paper, the stability of slope is analyzed according to two different failure modes. For the common homogeneous clay slope, it is assumed that the failure is caused by the crack at the top of the slope, and the criterion of slope stability is whether the crack length of the slope top reaches the critical crack length. The main research contents and conclusions are as follows: 1 using finite element software, according to the distribution of stress intensity factor at different positions of slope top to determine the most easily cracked position of slope, and then determine the critical joint length; At the most easily cracked position, the fracture larger than the critical fracture length is arranged, and the crack propagation angle is calculated to extend down in turn until the crack is through. The resulting fracture surface is the most dangerous sliding surface of the slope based on fracture mechanics. According to the ratio of stress intensity factors of type 鈪

本文編號(hào)：2349479