【摘要】：膨脹巖因強度相對較低,具有較為明顯蠕變特性。由于膨脹巖含有膨脹性礦物成分,具有吸水膨脹軟化特性,吸水軟化后其蠕變特性會更加明顯。本文用FLAC3D軟件分別以低含水率(7.415%)和高含水率(23.35%)的膨脹巖挖方邊坡為例開展了蠕變數(shù)值模擬研究,并在含水率為7.415%的膨脹巖挖方邊坡基礎上進行了不同降雨入滲深度和不同表面飽和層厚度條件下膨脹巖邊坡軟化蠕變數(shù)值模擬研究,得到了下面的結(jié)果：考慮蠕變作用的膨脹巖邊坡穩(wěn)定性更符合工程實際。低含水率(7.415%)膨脹巖邊坡在蠕變作用下呈整體蠕變運動趨勢,處于相對穩(wěn)定狀態(tài);高含水率(23.35%)膨脹巖邊坡在蠕變作用下易形成從坡腳至坡頂貫通的大剪應變增量帶而產(chǎn)生局部加速滑動。天然開挖及降雨入滲條件下膨脹巖邊坡蠕變,均以剪切破壞為主,在坡頂有拉破壞的可能。膨脹巖邊坡在降雨入滲時,會引起剪應力重分布,坡體內(nèi)剪應力會增大,隨入滲深度增加而更容易從坡面附近發(fā)生剪切破壞。在降雨入滲2m深度(表面0.5 m飽和)和降雨入滲7m深度(表面0.5 m飽和)兩種工況時,邊坡蠕變位移隨著入滲深度增大而增大,穩(wěn)定階段蠕變速率隨入滲深度增大而增大,但沒有出現(xiàn)滑坡。在降雨入滲3m深度(表面1m飽和)時,會很快出現(xiàn)表層條帶滑動,說明飽和層厚度對膨脹巖邊坡穩(wěn)定性影響大。
[Abstract]:The swelling rock has obvious creep characteristics because of its relatively low strength. The swelling rock contains expansive mineral components and has the characteristics of water absorption swelling and softening, and the creep property of the swelling rock will be more obvious after water absorption softening. In this paper, the creep numerical simulation of expansive rock excavation slope with low water content (7.415%) and high water content (23.35%) has been carried out using FLAC3D software. The numerical simulation of softening and creep of expansive rock slope with different rainfall infiltration depth and different surface saturation layer thickness was carried out on the basis of swelling rock excavation slope with 7.415% water cut. The following results are obtained: the stability of expansive rock slope considering creep is more in line with engineering practice. The swelling rock slope with low moisture content (7.415%) shows a whole creep movement trend under creep action and is in a relatively stable state. The swelling rock slope with high moisture content (23.35%) is easy to form a large shear strain increment zone from the foot of the slope to the top of the slope under the creep action resulting in local accelerated sliding. Under the condition of natural excavation and rainfall infiltration, the creep of expansive rock slope is mainly caused by shear failure, and there is a possibility of tensile failure at the top of the slope. When the expansive rock slope is infiltrated with rainfall, the shear stress will be redistributed, and the shear stress in the slope will increase, and the shear failure will occur more easily from near the slope with the increase of infiltration depth. When rainfall infiltration depth is 2m (surface 0.5 m saturation) and rainfall infiltration 7 m depth (surface 0.5 m saturation), the creep displacement of slope increases with infiltration depth, and creep rate increases with infiltration depth at stable stage. But there was no landslide. When rainfall infiltration depth is 3 m (surface 1 m saturation), the slip of surface zone will occur quickly, which indicates that the thickness of saturation layer has a great influence on the stability of expansive rock slope.
【學位授予單位】：廣西大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU452

【引證文獻】

相關會議論文 前1條

1 黃玉靈;陳明祥;;巖石蠕變對邊坡穩(wěn)定性影響的數(shù)值分析[A];巖土力學數(shù)值方法的工程應用——第二屆全國巖石力學數(shù)值計算與模型實驗學術(shù)研討會論文集[C];1990年

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本文編號：2267147