The Research On The Dynamic Compaction Effect Of The Duriously-shaped Rammer On Collapsible Loess Foundation

After nearly40years of development,dynamic consolidation is already a commonfoundation treatment method.This method generally use rammer of8~30t and dropdistance of8~20m to impack subsoil,produce shock waves in subsoil,let the subsoilbecome dense,and improve strength,improve the liquefaction resistance condition ofsandy soil,and eliminate loessial moist subsidence.Up to now，dynamic consolidationgenerally use flat rammer in the domestic and overseas,people know that cast steelmaterial is more excellent than concrete material,however,there are few specific study onthe effect of dynamic compaction of duriously-shaped rammer.This task improves the shape of mammer on the basis of the predecessors,changesthe contact form of rammer subface and subsoil,through the model test on collapsibleloess foundation in Taiyuan of Shan’xi Province,focuse on strengthening characteristicsof duriously-shaped rammer,and compare its effect with commen flat rammers’.Major achievements as follows:(1)To the duriously-shaped rammer in this task,light hammer with high drop distance has a better reinforcement effect than heavyhammer with low drop distance under same energy level;(2)The application range ofduriously-shaped rammer is about55%,the application range of plat rammer with holesis about75%,and the application range of plat rammer is about75%,the applicationrange of duriously-shaped rammer is shallow,the effect of reinforce to bottom is verylittle,so to the duriously-shaped rammer,tatol decrement of soil mass is maximum,but thedeep of dynamic compaction effective reinforcement is very small;(3)The extrusion onsurrounding soils caused by duriously-shaped rammer is smaller,so it can be used in theengineering which has small working face,big vertical space,and pre-existing buildingsor stuctures around,it can reduse the harmful influence to surroundings.