详情描述

Proposed modular intelligent heating equipment production and big data energy management center project, located in the Economic and Technological Development Zone of Dezhou City, Shandong Province. The project covers an area of 150 acres, with approximately 110 acres requiring dynamic compaction. The original site features a deep pit up to -6 meters, now filled but uneven, with tree roots and cultivated soil on the surface. The design employs dynamic compaction for ground treatment to meet the foundation design requirements.

Preparation Phase:
(1) Access Road: To ensure the smooth progress of the site leveling project, the construction of access roads is completed prior to the site leveling process. This also enhances safety measures. The width of the access road is no less than 5 meters, facilitating the entry and exit of heavy compaction machinery.
(2) Organize the on-site assembly of equipment, place the bulldozers and compaction equipment in position.
(3) Site leveling: The initial step involves using bulldozers and excavators to clear the surface vegetation, weeds, and other domestic waste from the backfill, roughly leveling the existing site to meet the requirements for machinery operation surfaces.
(4) To meet the construction environmental protection requirements, the land at the site is currently covered with a green mesh, following the principle of removing the mesh as the leveling progresses.
Adhere to the principle of incremental land leveling without large-scale operations, carrying out regional segmentation. Perform leveling and dynamic compaction in a continuous workflow; upon completion of dynamic compaction for a section, hand over the leveled area.

Compaction pile driving method, which involves dropping heavy hammers weighing from tens to hundreds of tons from heights ranging from several to dozens of meters to achieve dynamic compaction of the soil, thereby forcing it to become denser and reducing its compressibility while increasing its strength. This reinforcement method is primarily suitable for coarse-grained soils with particle sizes larger than 0.05mm, such as sandy soil, gravelly soil, loess soil, fly ash, mixed fill soil, backfill soil, low-saturation silt, clay, slightly expansive soil, and collapsible loess. The compaction pile driving method refers to a technique for rapidly consolidating soil layers by dropping heavy hammers from a certain height to improve the bearing capacity of weak foundations.
Also known as the dynamic consolidation method, it utilizes lifting equipment to elevate a 10 to 40-ton hammer to a height of 10 to 40 meters, allowing it to fall freely, compacting soil layers with the strong impact energy and shock waves. The dynamic compaction method is mainly used for sandy soils, unsaturated cohesive soils, and filled soil foundations. For unsaturated cohesive soil foundations, a method of continuous or intermittent blows is generally adopted; and the number of compactions and effective compaction depth are determined through on-site testing as needed for the project. Existing experience shows that under a compaction energy of 300 to 800 tons-meters, an effective compaction depth of 6 to 10 meters can usually be achieved.
Quantify ferric oxide and mica sheets, locally distributed in the area, with an average thickness of 1.77 meters. The original soil foundation bearing capacity characteristic value fak ≥ 120 kPa.
Groundwater Impact on Engineering:
The groundwater in this area belongs to the Quaternary aquifer. During the survey, the groundwater depth was measured at 1.62-3.52 meters. The primary recharge method for the groundwater is precipitation and upstream runoff, with an annual fluctuation range of 1.00-2.00 meters. The historical high water level was at 19.00 meters. The design elevation for the strong compaction work face in the northern part of the site is 20.6 meters, while in the southern high-fill area, it is 21.5 meters. The distance from the groundwater level to the compaction work face is less than 3 meters. Given the shallow groundwater depth in this project, the influence of groundwater must be considered in the strong compaction design. Under heavy blows of the compaction hammer, the pore water pressure in the foundation will rapidly increase, causing local groundwater levels to rise quickly and leading to the "rubber soil" phenomenon. Under limited construction conditions, a suitable construction plan must be adopted in conjunction with the on-site conditions to ensure that the groundwater level is controlled within a reasonable range during the foundation compaction. This is necessary to achieve a good foundation compaction effect. Otherwise, the foundation may "leak," leading to a rise in groundwater levels and a rapid increase in pore water pressure, causing the foundation to heave, which has consequences that are difficult to rectify.
Site preparation process before trial compaction:
1. All original topsoil and vegetation, including no less than 10cm of topsoil and roots, as well as domestic and construction waste, have been removed and transported out of the site using bulldozers.
2. Ensure the levelness of the construction site, using GPS and other surveying equipment to lay out the boundary lines and elevation controls (based on design requirements for zero elevation and independent foundation bottom elevation, calculate the site leveling elevation value from the total settlement after compaction), and use bulldozers for site leveling to ensure smooth operation of the compaction machinery.
3. The trial compaction area is located in the southern part of the laying-out exit zone. The area is approximately 15 meters long and 60 meters wide. Within the area, the land is leveled and the compaction points are marked with red bags.