【摘要】：巖土工程數(shù)值計算中粗粒土常采用鄧肯-張本構(gòu)模型,為了驗證該模型在軸向加載、卸載、側(cè)向加載等復(fù)雜應(yīng)力路徑條件下的適用性,進行了粗粒土的三軸試驗獲取其力學(xué)特性及本構(gòu)模型參數(shù);根據(jù)相似性原理制作了堆石壩的離心模型試樣,并采用與三軸試驗同樣級配與粒徑的粗粒土進行復(fù)雜應(yīng)力路徑的堆石壩離心模型試驗,試驗中通過改變離心加速度模擬加載、卸載,利用上游蓄水模擬壩體的側(cè)向加載;采用ABAQUS對離心模型試驗進行三維數(shù)值模擬,并研究了模型箱側(cè)壁摩擦系數(shù)與土體的初始應(yīng)力對數(shù)值結(jié)果的影響。通過比較離心模型試驗與數(shù)值模擬成果,表明土體的初始彈性模量對計算結(jié)果影響較大,初始應(yīng)力應(yīng)選擇自重作用下的應(yīng)力場;鄧肯-張本構(gòu)模型能較好地描述堆石壩的加載應(yīng)力路徑,而模擬卸載應(yīng)力路徑有一定的差異,需要改進鄧肯-張本構(gòu)模型中卸載模量的確定方法。
[Abstract]:In order to verify the applicability of the model in complex stress paths, such as axial loading, unloading and lateral loading, the Duncan-Zhang Ben model is often used in geotechnical engineering numerical calculation. The mechanical properties and constitutive model parameters of coarse grained soil were obtained by triaxial test. According to the similarity principle, the centrifuge model sample of rockfill dam is made, and the centrifuge model test of rockfill dam with complex stress path is carried out by using the same gradation and coarse grained soil as triaxial test. The centrifugal acceleration is simulated by changing the centrifugal acceleration in the test. Unloading, using upstream water storage to simulate the lateral loading of dam body; The three-dimensional numerical simulation of centrifugal model test was carried out by ABAQUS, and the effects of friction coefficient of the side wall of the model box and the initial stress of soil on the numerical results were studied. By comparing the results of centrifugal model test and numerical simulation, it is shown that the initial elastic modulus of soil has a great influence on the calculation results, and the initial stress should be chosen as the stress field under the action of self-gravity. The Duncan-Zhang Ben model can describe the loading stress path of rockfill dam well, but there are some differences in simulating unloading stress path, so it is necessary to improve the method of determining unloading modulus in Duncan-Zhang Ben model.
【作者單位】： 長江科學(xué)院水利部巖土力學(xué)與工程重點實驗室;
【基金】：國家自然科學(xué)基金項目(No.51309029,No.51309028) 水利部公益性行業(yè)科研專項(No.201201039)
【分類號】：TU411

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