河道淤泥氣泡混合輕質土剪切流變特性及模型

顧然　顧歡達

摘要：

利用剪切流變試驗對以水泥為固化劑的河道淤泥氣泡混合輕質土的流變特性進行了試驗研究。試驗結果表明，經固化處理的河道淤泥氣泡混合輕質土在荷載作用下具有類似于硬粘性土的流變特征。剪切流變可以分為3個階段：在剪應力水平較低時，剪切流變曲線呈衰減穩定型；隨著剪應力水平的提高，剪切流變曲線呈非穩定的等速型；當剪應力水平增大到一定程度時，剪切流變曲線呈加速型。河道淤泥氣泡混合輕質土的流變性隨著混合輕質土強度的提高而降低。根據試驗所呈現的剪切流變規律，可以發現河道淤泥氣泡混合輕質土的剪切流變符合七元件黏彈塑性剪切流變模型，模型能夠比較好地描述河道淤泥混合輕質土在各種剪應力水平下的衰減、等速以及加速流變過程。

關鍵詞：

河道淤泥；剪切流變；流變特性；剪切流變模型

中圖分類號：TU411

文獻標志碼：A文章編號：16744764（2017）02002609

Abstract：

The rheological properties of river sludge mixed with cement and air foam were studied by shear rheological test. The test results showed that under the load the mixed lightweight soil by curing process was similar to the rheological characteristics of hard clay. The soil rheological curve of air foamed soil using river sludge mainly presented three models. When the shear stress level was low， the theological curve appears as attenuation stable； When the shear stress levels continued to increase， the form of the rheological curve was not stable but constant speed type； When the shear stress increased to a certain extent， the rheological curve type was accelerated. With the improvement of the strength of the mixed lightweight soil， the rheological properties of river sludge mixed with cement and air foam is reduced. According to the test， the mixed lightweight soil shear rheological conformed to the sevencomponent viscoelastoplastic shear rheological model. Using the model can reasonably and reliably describe the rheological process include attenuation， velocity and acceleration of the mixed lightweight soil under various shear stress levels.

Keywords：

river sludge； shear rheological； rheological behavior； shear rheological model

中國長江三角洲地區河流交錯，池湖密布，經常年積累，在河道湖泊內產生了大量淤泥。這些長期沉積的淤泥不僅影響了水質，也影響了防洪、排澇、通航等各項功能的正常發揮。為了解決這些問題，需定期或不定期地對河道湖泊進行清淤，由此導致了大量疏浚淤泥產生。如何合理有效地循環利用這部分疏浚淤泥是當前環境巖土工程正在興起和發展的主要研究方向之一。

河道淤泥土屬于軟粘土范疇，考慮到流變現象廣泛存在于各種土體之中，特別是軟粘土中流變現象更為顯著，隨著時間的增長，土體中的應力和變形將產生不容忽略的變化。……