增压式真空预压现场应用研究综述OA

As an improved vacuum precompression foundation treatment method,air-booster vacuum preloading has been widely used,but its application effect varies in different projects.Based on engineering application cases doc-umented in the literature,the techniques,process parameters,and corresponding application effects of air-booster vacuum preloading were analyzed in this study,and the improvement directions was explored to provide references and guidance for engineering practice.The results show that pressurization pressure exhibits the most significant variation among the technical parameters.But successful application cases exist under different pressurization pres-sures;When pressurization pressure is higher or gas injection duration is prolonged,that a decrease in vacuum degree caused by gas leaking down along the pipe wall is a major factor contributing to unsatisfactory application results.Compared with conventional vacuum preloading methods,air-booster vacuum preloading increases ground surface settlement by 4.5％to 25.0％during the period.And more than half of the total settlement occurs within 10.0 m below ground surface.The compression rates is slightly higher in deeper strata.The vane shear strength of treated ground within pressurized pipe zones exceeds 1.15 times that achieved by conventional methods.Compared with direct vac-uum preloading,the vane shear strength of treated ground in the upper and middle lower sections of the booster pipe is weakened and strengthened respectively;The shear strengths are relatively close below the booster section.The sand free direct drainage technology plays a key role.Therefore,it is suggest that the air-booster vacuum preloading can be further studied and improved in real-time control of boosting,leakage prevention of boosting pipes,boosting process parameters and modes,and combined with thermal consolidation,biological(or chemical)reinforcement,and other foundation treatment methods as well to enhance application effect and efficiency.