Key Technical Points for Dynamic Compaction Foundation Construction
1. Carry out dynamic compaction replacement treatment of the foundation at the existing ground elevation.
2. After treatment, the characteristic value of the composite foundation bearing capacity shall be no less than 170 kPa.
3. The dynamic compaction replacement piers shall pass through the mucky silty clay and reach the red clay layer.
4. The layout of replacement pier points shall be carried out according to the design drawings, with a pier spacing of 2.5 m and a pier diameter of ≥1.4 m. The boundary of the dynamic compaction area shall extend 5.0 m beyond the building outline. Paper Reference Network.
5. The pier body material for dynamic compaction replacement shall use well-graded hard coarse-grained materials such as rubble, crushed stone, and slag, and the content of particles larger than 300 mm shall not exceed 30% of the total weight.
6. After foundation excavation, a compacted cushion layer of not less than 500 mm thick shall be laid on top of the piers, with its extent consistent with the dynamic compaction area. The cushion material shall be the same as the pier body material, with a particle size preferably not greater than 100 mm. The top elevation of the compacted cushion layer shall be the same as the bottom elevation of the foundation cushion.
Operating Conditions
1. Technical data such as geotechnical investigation reports, dynamic compaction site plans, and design requirements for dynamic compaction effects shall be available.
2. All above-ground and underground obstacles within the dynamic compaction area have been removed or demolished, and protective measures have been taken for those that cannot be removed.
3. The site has been leveled, access roads for machinery and equipment have been built, and the loose surface soil has been preloaded. During rainy season construction, drainage ditches have been dug around the perimeter to prevent surface water accumulation on the site.
4. A test area has been selected for dynamic compaction trials. Through trial compaction and testing, various technical parameters for dynamic compaction construction have been determined, and a dynamic compaction construction plan has been formulated.
5. When vibrations generated by dynamic compaction affect nearby adjacent buildings (structures), vibration reduction trenches shall be excavated on the side close to the buildings (structures) or appropriate reinforcement and vibration isolation measures shall be taken, and observation points shall be installed.
6. Conduct surveying and setting out, determine the control axes and the boundary lines of the dynamic compaction site, mark the compaction point positions with wooden stakes or white lime, and set up several benchmark points at locations unaffected by dynamic compaction.