The construction treatment of dynamic compaction project is to carry out necessary operations on the subgrade: machines and tools are used to fix and tamp the foundation. Adding lime soil into the subgrade and rolling in layers can improve the strength and flatness of the subgrade. In addition, the subgrade height shall comply with relevant standards.
1、 Verify the reliability of dynamic compaction method
The detection of reinforcement effect after dynamic compaction is an important basis to test the success or failure of construction. After dynamic compaction, quality inspection shall be carried out to check whether the reinforcement effect meets the design requirements, and further analyze whether the adopted construction parameters are reasonable. At present, there are three test methods used in China: static cone penetration test, standard penetration test and load plate test.
Cone head sensor is used to reflect the formation change in static cone penetration test. The method has the advantages of accuracy, simplicity, rapidity and continuous curve. After dynamic compaction, the variation law of formation strength is reflected.
Standard penetration method is a test technology widely used in geotechnical engineering. It belongs to dynamic penetration, which is generally combined with drilling. The probe rod of the hammer energy * fertilizer penetrometer is pressed into the soil, and it is easy to judge the nature of the soil according to the difficulty of penetration.
The foundation load plate applies load to the foundation soil on the bearing plate, and the load is transmitted to the foundation through the bearing plate. The deformation characteristics of foundation soil under natural conditions are measured and the bearing capacity of foundation is evaluated. The test results can provide an important basis for determining the bearing capacity of reinforced foundation.
After the soft soil subgrade is treated by dynamic compaction method, the foundation conditions are better and the effect is obvious. The treated foundation meets the design requirements and reduces the project cost. The construction quality of soft soil subgrade treated by dynamic compaction method is very important. Although the effect of dynamic compaction method is obvious, there will be some size problems in the process of Dynamic Compaction Engineering. Therefore, when this method is applied to the treatment of soft soil subgrade in the future, the construction process should be strictly controlled. Only by mastering all links in the construction can the scheme produce better economic and social benefits.
2、 Comparison of dynamic compaction construction machinery
Dynamic compaction machinery is the foundation of Dynamic Compaction Engineering. The selected construction equipment has dual effects, and the workload of dynamic compaction project is reduced by half.
1. Foreign construction machinery
Most developed countries in Europe use large tonnage crawler cranes to lift rammers. This kind of machine has the advantages of good stability and convenient walking. China's neighbor Japan adopts tire crane for dynamic compaction construction, and the effect is good.
2. Domestic construction machinery
In most dynamic compaction projects in China, only small tonnage cranes are used, only pulley blocks are used to lift the rammer, and automatic decoupling devices are used to make the rammer fall freely. The automatic decoupling device shall have sufficient strength and be flexible during construction. In order to prevent the crane frame from overturning when the hammer falls, corresponding protective measures shall be taken.