At present, the foundation of construction projects all need to be compacted with loose soil, which is inseparable from tamping. It needs to be tamped to a certain extent before it is qualified. In this way, there are some requirements on the indicators of the rammer, so a dynamic rammer is needed. Then the leasing personnel of the dynamic compaction machine introduced three different strengthening mechanisms of the dynamic compaction method.
1. Dynamic consolidation: when the dynamic consolidation method is applied to treat fine saturated clay, its reinforcement mechanism is the dynamic consolidation theory. During dynamic compaction, the huge impact energy generates a large stress wave in the soil, which destroys the original structure of the soil, causes local liquefaction of the soil and many cracks, increases the drainage channel, and makes the pore water escape smoothly. After the excess pore water pressure dissipates, the soil is consolidated. Due to the thixotropy of soft soil, the strength is restored.
2. Dynamic compaction: the dynamic compaction method is used to reinforce porous, coarse grained and unsaturated clay based on the mechanism of dynamic compaction, namely impact dynamic load, which reduces the pores in the soil and makes the soil dense, thus improving the strength of foundation soil. The compaction process of unsaturated soil is the process in which the gas phase (air) in the soil is squeezed out, and its compaction deformation is mainly caused by the relative displacement of soil particles.
3. Dynamic replacement: dynamic replacement can be divided into integral replacement and pile replacement. Integral replacement is to use dynamic compaction to squeeze the gravel into the sludge as a whole, and its mechanism is similar to that of soil replacement cushion. Pile type replacement is to fill gravel into soil through dynamic compaction, and some gravel piles (or piers) are tamped into soft soil at intervals to form pile type (pier type) gravel piles (piers). Its action mechanism is similar to that of gravel piles formed by vibroflotation method, forming a composite foundation as a whole.
The construction technology and operation of dynamic compaction are simple; It is applicable to a wide range of soil properties, with remarkable reinforcement effect, and can achieve high bearing capacity. The general foundation strength can be increased by 2~5 times; The compressibility can be reduced by 2~10 times, and the reinforcement depth can reach 6~10m; High efficiency and fast construction speed (5000~10000m foundation can be reinforced by general equipment every month), which can shorten the construction period by half compared with backfilling and pile foundation; Save reinforcement raw materials; The construction cost is low, saving investment, 50% less than the cost of soil replacement and backfilling, and 50%~70% less than the investment of prefabricated pile foundation reinforcement.
Dynamic compaction method can not only improve the strength of foundation soil, reduce its compressibility, but also improve the ability to resist vibration liquefaction and eliminate soil collapsibility. Therefore, it is not only applicable to the treatment of gravel soil, sandy soil, silt, cohesive soil, miscellaneous fill and plain fill foundation, but also often used to treat liquefiable sand soil foundation and collapsible loess foundation. Follow us http://www.sddhfjx.cn , learn more about it!