本文關(guān)鍵詞： 重力錨邊坡 粗粒土 直剪蠕變試驗 顆粒級配 長期穩(wěn)定性　出處：《西南交通大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：在山區(qū)道路工程建設(shè)中常常會遇到粗粒土邊坡,粗粒土的工程性質(zhì)直接決定著工程邊坡的穩(wěn)定性,其蠕變變形特性對邊坡的長期穩(wěn)定性有重要影響。本文依托四川雅安至康定高速公路滬定大渡河橋位由粗粒土構(gòu)成的重力錨邊坡工程,通過普通直剪試驗和直剪蠕變試驗研究了粗粒土的力學(xué)性質(zhì),分析了顆粒級配和含水量的變化對其蠕變特性的影響,進(jìn)而通過Flac3D數(shù)值模擬分析了成橋后重力錨邊坡的長期穩(wěn)定性。主要研究工作及結(jié)果如下:(1)針對橋位重力錨邊坡的粗粒土進(jìn)行現(xiàn)場取樣,在原土樣的基礎(chǔ)上配制了 3種不同顆粒級配的粗粒土試樣,采用普通直剪試驗和改制的直剪蠕變試驗測試了不同含水量情況下的不同試驗土樣的力學(xué)特性,得到該試樣的長期抗剪強(qiáng)度約為快剪強(qiáng)度的0.7～0.8倍,試樣摩擦角降低2°左右。(2)隨著粒徑大于5mm的顆粒含量P5的增加,試樣長期粘聚力c∞值逐漸降低,長期內(nèi)摩擦角Φ∞值逐漸增加,同普通直剪試驗得到的抗剪強(qiáng)度指標(biāo)變化規(guī)律相似。土樣含水量由10%降至5%,Φ∞約增加2°,c∞值則提高約30%。(3)利用Matlab程序?qū)υ囼灉y得的土樣蠕變曲線進(jìn)行擬合,符合Burgers模型基本特征。通過對試樣的Maxwell及Kelvin單元剪切模量及粘滯系數(shù)計算分析,得到了在不同豎向壓力和剪切應(yīng)力作用下試樣的P5對初始剪切模量G1、長期剪切模量G2、黏滯系數(shù)η1和黏滯系數(shù)η2的影響規(guī)律。隨著P5增加,G1基本不變,但G2、η1和η2隨之逐漸減小。(4)基于試驗確定的土體蠕變特性,采用Flac3D三維數(shù)值模擬方法分析了重力錨邊坡的長期穩(wěn)定性。結(jié)果表明,大渡河橋重力錨邊坡在5年內(nèi)的穩(wěn)定性良好,錨碇朝大渡河方向位移增加值為13.59cm,處于有效工作狀態(tài)。對比3種級配的土體試樣,得到在土體顆粒級配P5=20.7%時,錨碇朝大渡河方向位移增加值最小。本文研究確定的橋位重力錨邊坡粗粒土蠕變特性,及相關(guān)的邊坡長期穩(wěn)定性分析結(jié)果,可為工程實際提供重要參考。
[Abstract]:The coarse grained soil slope is often encountered in the mountain road engineering construction. The engineering properties of the coarse grained soil directly determine the stability of the engineering slope. The creep deformation characteristics have an important effect on the long-term stability of the slope. This paper relies on the gravity anchor slope engineering of the Dadu River bridge of the Ya'an to Kangding expressway in Sichuan province. The mechanical properties of coarse grained soil were studied by normal direct shear test and direct shear creep test, and the effects of particle gradation and water content on the creep properties were analyzed. Then the long-term stability of gravity anchor slope after completion of the bridge is analyzed by Flac3D numerical simulation. The main research work and results are as follows: 1) sampling the coarse soil of gravity anchor slope at bridge site. Three kinds of coarse grained soil samples with different gradation were prepared on the basis of original soil samples. The mechanical properties of different test soil samples with different water content were tested by normal direct shear test and modified direct shear creep test. The long-term shear strength of the sample is about 0.7 ~ 0.8 times of that of the fast shear strength, and the friction angle of the sample is reduced by about 2 擄. 2) with the increase of the particle content P _ 5 when the diameter is larger than 5 mm. The long-term cohesion C 鈭，

本文編號：1490311