摘要
水敏性火山灰沉积岩具有很强的吸水性和膨胀性,遇水后迅速软化崩解,钻孔施工时使用普通泥浆很难成孔。通过分析泥浆护壁性状,认为减少失水量和泥皮厚度是在水敏性土中成孔和提高桩侧摩擦阻力的关键。选取羧甲基纤维素(CMC)和纯碱(Na2CO3)作为减小失水量的添加剂,通过正交试验确定泥浆的最佳质量配比为:淡水∶膨润土∶CMC∶纯碱=100∶8∶0.1∶0.04。试验结果表明:膨润土质量分数越大,泥皮越厚,护壁效果越好,对桩侧摩擦阻力的消弱越大;CMC和纯碱对减少失水量和泥皮厚度效果明显;海水入浸会增加泥浆的失水量,造成泥浆恶化;铬铁木质素磺酸钠盐(FCL)对因海水入浸而恶化的泥浆改善效果不明显。
The pozzuolana sedimentary soil falls into the water-sentimental soil, which has the nature of strong absorption and expansion. It is prone to be softened and collapsed when meeting water. Consequently, the collapse of hole will easily occur with the common slurry mixture ratio. In order to confect the proper slurry for the boring suitable for the water-sentimental soil, the means of reducing water loss of slurry is the key to minimizing collapse. With CMC （carboxymethyl cellulose） and sodium carbonate as additives, the best slurry mixture ratio based on the orthogonal test is.. freshwater： bentonite ： CMC ： sodium carbonate= 100 ： 8 ： 0. 1 ： 0.04. The test results show that if the content of bentonite is higher the slurry interlayer is thicker and the result of protection is better. But the reducing of friction is higher. CMC and sodium carbonate are effective for reducing water loss of slurry and thickness of slurry interlayer. Seawater immerging slurry can increase the water loss and make it deteriorative. FCL （Fe Chrominium Sodium Lignin Sulfonate） has no much availability for this deterioration. 3 tabs, 5 figs, 11 refs.
出处
《长安大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2007年第6期67-71,共5页
Journal of Chang’an University(Natural Science Edition)
基金
湖南省重点交通科技项目(湘科计字[2004]101-04SK2008)
关键词
桥梁工程
火山灰沉积岩
泥浆
正交试验
bridge engineering
pozzuolana sedimentary soil
slurry
orthogonal test
