用振动水冲法加密砂基,可提高砂基承载力,消除可液化性,提高抗震稳定性;用振冲法在松软地基中制造碎石桩组成复合地基可提高承载力,减少沉降。此法与其他地基加固法比较,可节约钢筋、水泥和木材,且施工简单,费用低廉,加固期短。因此,振冲法是一种适合我国国情的快速加固法。振冲施工前应详细了解工程地质资料和设计资料,以便掌握上部荷载情况,基础结构形式,地层分布和土质特性。较为复杂的土质还必须补孔钻探,以进一步了解土质分布的均匀程度,软弱夹层及其厚度。对于回填土的场地尚需注意地面下有无障碍物,否则会影响施工进展。对于一些重要工程,宜在加固区土质相同的地方,进行实地制桩试验,以核实地基土质情况以及各层土质对制桩的反映,取得具体数据,以指导加固区碎石桩施工。由于振冲法加固松软地基属于隐蔽工程,需严格控制施工质量和加固效果的检验。从工程实践中,许多单位都积累了很多经验,对加固机理、设计计算提出一些看法,机具设备和检验方法也有些改进和发展。如提出碎石桩在复合地基中起着桩体、垫层和沙井的作用;检验施工质量三要素的控制及相互配合;用动力触探检验碎石桩的质量和加固效果;设计成功控制施工现场质量的振冲施工自动记录仪;用橡胶减振器代替万向节,改进振冲器性能,延长振冲器使用寿命等。这些成果必将促进振冲加固地基法的进一步发展。 Encrypting the sand base with vibratory water jetting method can improve the bearing capacity of the sand base, eliminate the liquefaction, and improve the seismic stability. The use of vibroflotation to make the gravel piles in the soft ground to form a composite foundation can improve the bearing capacity and reduce the settlement. Compared with other foundation strengthening methods, this method can save steel, cement and wood, and has simple construction, low cost and short reinforcement period. Therefore, vibroflotation method is a kind of rapid reinforcement method suitable for China’s national conditions. Before the vibroflotation, the engineering geological data and design data should be understood in detail in order to understand the upper load conditions, the basic structure, the stratum distribution and the soil properties. Complicated soils must also be drilled with holes to further understand the uniformity of soil distribution, weak interlayers and their thickness. For the site of backfill soil, attention must be paid to obstacles on the ground, otherwise it will affect the construction progress. For some important projects, it is advisable to carry out on-site pile-making tests at the same soil in the reinforced area to verify the soil conditions of the foundation and the reflection of each layer of soil on the piles, and obtain specific data to guide the construction of the gravel piles in the reinforced area. Because vibroflotation method is a concealed project for the reinforcement of soft ground, it is necessary to strictly control the inspection of construction quality and reinforcement effect. From the engineering practice, many organizations have accumulated a lot of experience, put forward some views on the reinforcement mechanism, design calculations, and some improvement and development of machine tools and inspection methods. For example, gravel piles are proposed to act as piles, cushions and manholes in composite foundations; to inspect the control and cooperation of the three elements of construction quality; to test the quality and reinforcement effect of gravel piles with dynamic penetration testing; and to successfully control the construction of the design. Field quality vibratory construction automatic recorder; use rubber shock absorbers instead of universal joints, improve vibrator performance, extend the vibrator service life. These achievements will surely promote the further development of the vibroflotation and strengthening foundation method.