摘要
结合高钙粉煤灰与上海浦东国际机场二期促淤软土拌和后加固土体的室内外试验,指出高钙粉煤灰是加固促淤软土地基的一种新型材料。基于在不同掺灰量、不同游离氧化钙含量和添加不同激发剂情形下拌和灰土的室内物理力学性能试验,探讨了高钙粉煤灰加固促淤软土的固化机理和工程特性,加固后土体在无侧限抗压强度、变形、渗透特性以及抗液化能力等方面均有明显改善,指出灰土强度与掺灰量、土体改性激发剂的品种和数量以及养护龄期有关,高钙灰与土体拌和后自膨胀特性下降为12%,消除了高钙灰的体积不稳定问题。现场进行粉喷桩加固软土地基试验表明,复合软土地基的极限承载力达到240kPa以上,可以替代水泥土搅拌桩,桩间土体强度和变形也得到改善。加固场地地下水质分析表明,高钙灰加固促淤软土地基不会影响地下水质和环境。
Based on laboratory and field tests on the reclaimed soft land in Shanghai Pudong International Airport (phase two) improved by high calcium fly ash (ASTM class c fly ash), it is pointed out that the high calcium fly ash is a new kind of material used for reclaimed soft soil stabilization. Stabilization mechanism and some engineering behaviors of reclaimed soft soil improved by high calcium fly ash were discussed based on the tests of mechanical and physical properties of stabilized soils. The results of laboratory tests show that the unconfined compressive strength, deformation, seepage and liquefaction potential of improved soils were obviously improved and the moisture content and void ratio of soils were decreased by comparison of mechanical and physical properties of stabilized soils with natural soils, strengths of stabilized soft soils was depended on the usage content of fly ash, type and additive content of soil-improved agent and aging. Expansive tests of improved soils show that the self-expansion values of high calcium fly ash mixed with soft soil were decreased by 12 percent and the problem of unstable volume for fly ash was overcome. The field tests on the reclaimed soft soil stabilized by dry jetting method (DJM) with high calcium fly ash were carried out. The results show that the ultimate bearing capacity of composite foundation was improved and was up to 240 kPa, which is satisfactory for the foundation design for low-rise building on reclaimed land instead of DJM with cements, and the strength and deformation of soils between the DJM pile were also improved. The environmental aspects of high calcium content fly ash in soil stabilization were analyzed on the basis of monitoring the components of the material and underwater on the stabilized soil site. The measurement results show non-negative effect on underwater and environment.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2004年第5期783-788,共6页
Rock and Soil Mechanics
基金
上海粉煤灰开发利用基金
上海市建设技术发展基金资助项目(NO。99A101017)。
关键词
高钙粉煤灰
促淤软土
固化机理
粉喷桩
复合地基
环境特性
Airports
Bearing capacity
Calcium
Foundations
Mechanical properties
Physical properties
Soils
Stabilization
