團(tuán)粒尺寸對(duì)飽和紅黏土動(dòng)力特性影響試驗(yàn)研究

摘要： 廣泛用于路基填料的紅黏土容易膠結(jié)成不同團(tuán)粒結(jié)構(gòu)，從而對(duì)土體的動(dòng)力特性產(chǎn)生重要影響。為探究團(tuán)粒尺寸對(duì)飽和紅黏土動(dòng)力特性的影響，運(yùn)用GDS動(dòng)三軸儀對(duì)最大團(tuán)粒尺寸Dmax分別為5.0＼，2.0和0.5 mm制備的飽和壓實(shí)樣，開展不同循環(huán)應(yīng)力比的循環(huán)荷載不排水三軸試驗(yàn)，以探究土體的動(dòng)軸向應(yīng)變、動(dòng)彈模量以及阻尼比隨團(tuán)粒尺寸的演化規(guī)律。具體結(jié)論如下：（1） 累積動(dòng)軸向應(yīng)變隨循環(huán)次數(shù)增多而增大的演化規(guī)律主要集中于循環(huán)次數(shù)為200次的范圍內(nèi);累計(jì)動(dòng)軸向應(yīng)變隨循環(huán)應(yīng)力比的增大呈指數(shù)型增長。（2） 考慮容許循環(huán)應(yīng)力比之前，越大團(tuán)粒尺寸制備試樣所產(chǎn)生的累積動(dòng)軸向應(yīng)變?cè)酱?考慮容許循環(huán)應(yīng)力比之后，越大團(tuán)粒尺寸制備試樣所產(chǎn)生的累計(jì)動(dòng)軸向應(yīng)變反而越小。（3） 不同團(tuán)粒尺寸試樣在同一循環(huán)應(yīng)力比作用下，土體動(dòng)彈模量和阻尼比隨振動(dòng)次數(shù)的增加逐漸趨于一致，表明團(tuán)粒尺寸只在循環(huán)荷載作用初期對(duì)動(dòng)彈模量和阻尼比產(chǎn)生重要影響。

關(guān)鍵詞： 飽和紅黏土; 動(dòng)三軸試驗(yàn); 團(tuán)粒尺寸; 循環(huán)應(yīng)力比; 動(dòng)力特性

中圖分類號(hào)： P319.56""""" 文獻(xiàn)標(biāo)志碼：A"" 文章編號(hào)： 1000-0844（2025）02-0270-11

DOI：10.20000/j.1000-0844.20230731001

Experimental study on the effect of aggregate size on the

dynamic characteristics of saturated red clay

CHEN Bo^1，2， YANG Tianchen1， JIN Pan2

（1. School of Civil Engineering， Anhui Jianzhu University， Hefei 230601， Anhui， China;

2.College of Civil Engineering and Architecture， Quzhou University， Quzhou 324000， Zhejiang， China）

Abstract：

The use of red clay， a widely-used material for subgrade-filling， easily results in the formation of an aggregate structure with different sizes， which means it has an important influence on the dynamic characteristics of soil. With the goal of investigating the effect of aggregate size on the dynamic characteristics of saturated red clay， a series of consolidation-undrained dynamic triaxial tests under different cyclic stress ratios were conducted in this study on compacted specimens prepared with different aggregate sizes （Dmax =5.0， 2.0 and 0.5 mm） using the dynamic triaxial apparatus GDS. The evolution of dynamic axial strain， dynamic elastic modulus， and damping ratio with aggregate size was analyzed. Several key findings are obtained. （1） The obvious increase in cumulative dynamic axial strain with increasing cyclic number is concentrated within the first 200 cycles， and such axial strain exhibits exponential growth as the cyclic stress ratio increases. （2） The more cumulative dynamic axial strain is observed from specimens prepared with larger aggregate sizes before the allowable cyclic stress ratio. In comparison， more cumulative dynamic axial strain is observed from specimens prepared with smaller aggregate sizes after the allowable cyclic stress ratio. （3） Under the same cyclic stress ratio， the dynamic elastic modulus and damping ratio of specimens with different aggregate sizes， almost align with the same growth tendency as the vibration times increased， thus indicating that the influence of aggregate size on dynamic elastic modulus and damping ratio is only obvious in the initial stage of cyclic loading.

Keywords：

saturated red clay; dynamic triaxial test; aggregate size; cyclic stress ratio; dynamic characteristics

0 引言

紅黏土是碳酸鹽類巖石，在亞熱帶溫濕氣候下，經(jīng)過風(fēng)化、殘積、坡積或殘坡積而成的一種高塑性黏土，廣泛分布于我國云貴高原、廣西、鄂西、湘西等地區(qū)^［1］。紅黏土作為一種區(qū)域性特殊土，具有相對(duì)較好的變形、強(qiáng)度等力學(xué)特性。因此，紅黏土作為一種不錯(cuò)的天然填料，廣泛應(yīng)用于道路、鐵路等基礎(chǔ)設(shè)施的路基填筑工程^［2-3］?！?br>