地震工程学报Issue(4)：820-823,4.DOI:10.3969/j.issn.1000-0844.2014.04.0820
降低黄土液化势的改性技术分析
Analysis of Modification Technique for Reducing Loess Liquefaction Potential
摘要
Abstract
Loess in China are mainly distributed in the terraces of the Yellow River,including in the Gansu,Ningxia,Inner Mongolia,and Shanxi provinces,covering an area of 6.4×10 6 km2 that accounts for about 6.6% of China's territory.The loess in western Gansu belongs to the class of unsaturated loess with a wide distribution range.Formed near the sand source,the eolian loess mainly includes sand loess,low-viscosity loess,and clay loess. <br> Low-viscosity loess in Gansu has large thickness,with development pores and aerial weak cementation,which under dynamic loading is likely to produce large settlement deformation.It also has strong water-collapse characteristics and a tendency toward liquefaction.Such material brings arduous engineering challenges and foundation treatment construction problems.Low-vis-cosity loess in general has weak alkaline and poor cementation strength,with large deformation under a force dynamic.Because underground water easily uplifts after loading,liquefaction is a serious problem.Acid-modified and chemically modified technology can effectively improve the loess seismic subsidence problem. <br> The principle of acid-modified loess chemical modification is using phosphoric acid and a weak acid as a loess acidification treatment,considering that the loess formed in a dry climate gives priority to calcium carbonate.Then,other salts (Boric salt)are added to form the cementa-tion bonds such as boron bridge bonding and hydrogen bonding.Filling material (calcium salt)is added to adjust the ratio of particle size to reduce the liquefaction potential.The acid-modified method reduces the low-cohesion loess'ability to liquefy.The liquefaction test showed that under 50~65 kPa dynamic stress,the modified loess had a very slow rise in pore water pressure ,a ver-y small deformation,and almost no stress reduction.Under a dynamic stress of 65 kPa,its lique-fied deformation was no more than 0.2%,corresponding to resistance to an IX-level earthquake. The following ratio was confirmed:10% ~ 30% calcium,6% ~ 13% boron material with 3%phosphoric acid.If a higher level of anti-seismic resistance is required,add 8%~ 13% of boron material. <br> The acid-modified method creates no chemical toxicity,and the price of the raw boron mate-rial is lower than that of the lime cement.Therefore,this method has some economic and social benefits.关键词
黄土/黄土液化/改性技术Key words
loess/loess liquefaction/modification technique for loess分类
天文与地球科学引用本文复制引用
邓津,王兰民,程菊红,丙慧,车高凤..降低黄土液化势的改性技术分析[J].地震工程学报,2014,(4):820-823,4.基金项目
2013中国地震局黄土重点室开放基金“基于微观机理的场地响应分析”(KLLEE-12-001) （KLLEE-12-001）
国家自然科学基金资助项目(50978239,41371090) （50978239,41371090）
