Experimental Study On The Reinforcement Of Shallow Weak Foundation With Integral Carbonization Method

Relying on the “Research on the Application of Integral Carbonization Technology to Strengthen the Shallow Soft Foundation of Expressway”(2018T01)of Jiangsu Provincial Department of Communications Scientific Research Fund,the application of magnesium oxide integral carbonization and reinforcement technology,selected part of the shallow soft foundation of Changyi and Yichang Expressway The method of combining experiment,long-term monitoring and theoretical analysis was studied.Through the research and development of construction equipment,combined with field tests,reinforcement effect detection and subgrade reverse monitoring,a complete set of technology for construction,monitoring and quality evaluation has been formed.The main content and results are as follows:(1)Aiming at the construction technology of magnesium oxide integral carbonized shallow soft ground,the integral carbonization mechanical equipment and integral carbonization system were developed.The system is equipped with a stirring device,a curing agent supply device,and an aeration carbonization device through a crawler excavator,which effectively injects and agitates the shallow soft soil,and completes the reinforcement of the weak foundation within a few hours of aeration carbonization.(2)Through the research on the construction technology of the soft foundation of the magnesia integral carbonized shallow layer,the construction technology of preparation of the construction materials,mixing of the weak soil,the arrangement of the aeration system,aeration carbonization,etc.were determined.Weak method of foundation construction technology and construction process.(3)Through the in-situ test,the treatment effect of the shallow carbon soft soil reinforced by the integral carbonization method is studied.The results show that the soil body can obtain the dynamic rebound modulus and the improvement of the foundation bearing capacity after carbonization in a short time.The dynamic rebound modulus of some carbide areas has reached more than 20 MPa,and the foundation bearing capacity of each measuring point on the site has exceeded 100 k Pa,which meets the requirements of engineering construction for foundation bearing capacity.(4)Using in-situ monitoring technology,a part of the subgrade replacement effect and soil stress after magnesium oxide integral carbide treatment were studied.The subgrade replacement gradually offsets within 70 mm,and the soil consolidation effect is good;carbonization The earth pressure at each measuring point on the subgrade also returned to about 132 k Pa in about 120 days.(5)Combined with the construction process,the carbonation effect under different carbonation time and vent pipe distance,the foundation bearing capacity after carbonization,dynamic rebound modulus and long-term reduction amount were analyzed,and the weak soft foundation of magnesium oxide as a whole was proposed.Technical quality control methods.(6)Compared with the traditional shallow soft soil foundation treatment method,the integral carbonization method for strengthening shallow soft soil is environment-friendly and resource-friendly.The cost of processing unit cubic muddy soil can be reduced by about 17%compared with the traditional replacement method.The advantages are significant.