In the construction project, due to the need to compact the loose soil, dynamic rammer is often used. There are many types of dynamic compaction machines, such as frog type, vibration type, jump type, ramming type and lifting hammer type. According to the needs of the project, different types of dynamic compaction machines are used.

强夯锤质量可取 10～40t，其底面形式宜采用圆形或多边形，锤底面积宜按土 的性质确定，锤底静接地压力值可取25～40kPa，对于细颗粒土锤底静接地压力宜取较小值。锤的底面宜对称设置若干个与其顶面贯通的排气孔，孔径可取250～ 300mm。强夯置换锤底静接地压力值可取100～200kPa。

The weight of dynamic rammer is 10-40t, and its bottom form should be round or polygonal. The area of hammer bottom should be determined according to the properties of soil. The static grounding pressure of hammer bottom can be 25-40kpa. For fine-grained soil, the static grounding pressure should be smaller. The bottom surface of the hammer should be symmetrically arranged with a number of vent holes through its top surface, and the hole diameter can be 250-300 mm. The static grounding pressure at the bottom of dynamic compaction replacement hammer can be 100 ~ 200KPa.

施工机械宜采用带有自动脱钩装置的履带式起重机或其他专用设备。采用履带式起重机时，可在臂杆端部设置辅助门架，或采取其他措施，防止落锤时机架倾覆。

Crawler crane with automatic decoupling device or other special equipment should be used for construction machinery. When crawler crane is used, auxiliary gantry can be set at the end of boom, or other safety measures can be taken to prevent the frame from overturning when falling hammer.

当场地表土软弱或地下水位较高，夯坑底积水影响施工时，宜采用人工降低地下水位或铺填一定厚度的松散性材料，使地下水位低于坑底面以下2m。坑内或场地积水应及时排除。

When the surface soil is weak or the underground water level is high, and the ponding at the bottom of the ramming pit affects the construction, it is advisable to manually lower the groundwater level or pave with a certain thickness of loose materials to make the groundwater level lower than 2m below the pit bottom surface. The ponding in the pit or site should be removed in time.

施工前应查明场地范围内的地下构筑物和各种地下管线的位置及标高等，并采取必要的措施，以免因施工而造成损坏。

Before construction, it is necessary to find out the location and elevation of underground structures and various underground pipelines within the site, and take necessary measures to avoid damage caused by construction.

当强夯施工所产生的振动对邻近建筑物或设备会产生有害的影响时，应设置监测点，并采取隔振或防振措施强夯对邻近建筑物的有害影响。

When the vibration produced by dynamic compaction will have harmful effects on adjacent buildings or equipment, monitoring points should be set up and vibration isolation or anti vibration measures should be taken to eliminate the harmful impact of dynamic compaction on adjacent buildings.