Dynamic compaction method is to use lifting machinery (crane or crane equipped with tripod, gantry) to transfer large tonnage (generally 8~ When the rammer is lifted to a height of 6-30 m, it falls freely, which gives strong impact energy to the foundation soil, resulting in shock wave and large impact stress in the soil, forcing the soil pore to compress and liquefy the soil, forming cracks around the tamping point, forming a good drainage channel, pore water and gas escaping, so as to rearrange the soil material, achieve consolidation after aging compaction, and then realize consolidation It is an effective method to improve the bearing capacity of foundation and reduce its compressibility.

强夯法加固的特点是：施工工艺、操作简单；适用土质范围广，加固效果显著；变形沉降量小，土粒结合紧密，有较高的结构强度；工效高，施工速度快；节省加固原材料；施工费用低，节省投资。

The characteristics of dynamic consolidation method are: simple construction technology and operation; wide range of applicable soil, significant reinforcement effect; small deformation and settlement, close combination of soil particles, high structural strength; high work efficiency and fast construction speed; saving reinforcement raw materials; low construction cost and investment saving.

1、机具设备

1. Machinery and equipment

1)夯锤：用钢板作外壳，内部焊接钢筋骨架后浇筑C30混凝土，或用钢板做成组合成的夯锤，以便于使用和运输。夯锤底面有圆形和方形两种，圆形不易旋转，定位方便，稳定性和重合性好，采用较广；锤底面积宜按土的性质和锤重确定，锤底静压力值可取25～40kPa;对于粗颗粒土（砂质土和碎石类土）选用较大值，一般锤底面积为3～4m?；对于细颗粒土（粘性土或淤泥质土）宜取较小值，锤底面积不宜小于6m?。一般10t夯锤底面积用4.5m?，15t夯锤用6m?较适宜。锤重一般为8、10、12、16、25t。夯锤中宜设1～4个直径250~ 300mm上下贯通的排气孔，以利空气迅速排走，减小起锤时，锤底与土面间形成真空产生的强吸附力和夯锤下落时的空气阻力，以保证夯击能的有效性。

1) Rammer: steel plate is used as shell, and C30 concrete is poured after internal welding of reinforcement framework, or steel plate is made into a combined rammer for easy use and transportation. There are two types of hammers: round and square, which are not easy to rotate, convenient for positioning, good stability and coincidence, and are widely used; the area of hammer bottom should be determined according to the properties of soil and hammer weight, and the static pressure value of hammer bottom can be 25 ~ 40kpa; For coarse-grained soil (sandy soil and gravel soil), the hammer bottom area is generally 3-4m?; for fine-grained soil (cohesive soil or muddy soil), the hammer bottom area should not be less than 6m?. Generally, the bottom area of 10t rammer is 4.5m, and that of 15t rammer is 6m. The hammer weight is generally 8, 10, 12, 16, 25 t. One to four vent holes with a diameter of 250-300 mm should be set up in the rammer to facilitate the rapid exhaust of air, reduce the strong adsorption force generated by the vacuum between the hammer bottom and the soil surface and the air resistance when the hammer falls, so as to ensure the effectiveness of the ramming energy.

2)起重设备：由于履带式起重机低，稳定性好，行走方便，多使用起重量为15t、20t、25t、30t、50t的履带式起重机（带摩擦离合器）。

2) Lifting equipment: due to the low center of gravity, good stability and convenient walking of crawler crane, crawler cranes with lifting capacity of 15t, 20t, 25t, 30t and 50t are mostly used (with friction clutch).

3)脱钩装置：采用履带式起重机做强夯起重设备，国内目前使用较多的是通过动滑轮组用脱钩装置来起落夯锤。脱钩装置要求有足够的强度，使用灵活，脱钩快速、。常用的工地自制自动脱钩器由吊环、耳板、销环、吊钩等组成。

3) Unhooking device: crawler crane is used as dynamic compaction lifting equipment. At present, it is widely used in China to lift and lower the rammer by means of moving pulley block and unhooking device. The unhooking device should have enough strength, flexible use, fast and safe decoupling. The commonly used self-made automatic decoupling device is composed of lifting ring, ear plate, pin ring and hook.

4)锚系设备：当用起重机起吊夯锤时，为防止夯锤突然脱钩使起重臂后倾和减小对臂杆的振动，应用T1-100型推土机一台设在起重机的前方做地锚，在起重机臂杆的顶部与推土机之间用两根钢丝绳连系锚旋。钢丝绳与地面的夹角不大于30°，推土机还可用于夯完后做表土推平、压实等辅助性工作。当用起重三角架、龙门架或起重机加辅助桅杆起吊夯锤时，则不用设锚系设备。

4) Anchoring equipment: when lifting the rammer with a crane, in order to prevent the hammer from suddenly unhooking and make the crane boom backward tilt and reduce the vibration to the boom, a t1-100 bulldozer is used as the ground anchor in front of the crane, and two steel wire ropes are used to connect the top of the crane boom and the bulldozer. The angle between the wire rope and the ground is not more than 30 ° and the bulldozer can also be used for surface soil leveling and compaction after compaction. When the hammer is lifted by lifting tripod, gantry or crane plus auxiliary mast, it is unnecessary to install anchoring equipment.

2、工艺流程

2. Process flow

清理、平整场地→标出第遍夯点位置、测量场地高程→起重机就位、夯锤对准夯点位置→测量夯前锤顶高程→夯锤起吊→务锤脱钩自由下落夯击→往复夯击，满足夯击次数及控制标准，完成一个夯点的夯击→重复以上工序，完成一遍全部夯点的夯击→填平夯坑，测量场地高程→停歇规定时间间隔，重复上述程序逐次完成全部夯击遍数→用低能量满夯，将场地表层松土夯实，并测量夯后场地高程

Clearing and leveling the site → marking the location of the first tamping point and measuring the elevation of the site → placing the crane in place and aligning the rammer with the tamping point → measuring the top elevation of the hammer before ramming → lifting the rammer → keeping the hammer uncoupling and falling freely → ramming repeatedly to meet the tamping times and control standards, complete the tamping of one tamping point → repeat the above process, complete the tamping of all tamping points → fill the tamping pit and measure Measure the site elevation → stop the specified time interval, repeat the above procedures to complete all compaction times one by one → use low energy full compaction to loosen the soil on the site surface, and measure the site elevation after compaction

适用于加固碎石土、砂土、低饱和度粉土、粘性土、湿陷性黄土、高填土、杂填土以及“围海造地”地基、工业废渣、垃圾地基等的处理；也可用于防止粉土及粉砂的液化，或降低大孔土的湿陷性等级；对于高饱和度淤泥、软粘土、泥炭、沼泽土，如采取一定技术措施也可采用，还可用于水下夯实。强夯不得用于对工程周围建筑物和设备有一定振动影响的地基加固。

It is suitable for the treatment of gravel soil, sandy soil, low saturation silt, cohesive soil, collapsible loess, high fill, miscellaneous fill, and the foundation of "reclaiming land from the sea", industrial waste residue, garbage foundation, etc.; it can also be used to prevent the liquefaction of silt and silt, and eliminate or reduce the collapsibility grade of macroporous soil; for high saturation silt, soft clay, peat, swamp soil, if the Technical measures can also be adopted, and can be used for underwater compaction. Dynamic compaction shall not be used for foundation reinforcement which has certain vibration effect on buildings and equipment around the project.