I  Project Overview

1. Project Introduction：

The project is located in the hilly area of Shenjing Town, southern Xuanhua County, Hebei Province, with a total installed capacity of 70MW.

2. Construction Geological Conditions：

The site is a hilly landform, and its construction area is high in the west and low in the east, with an altitude of about 1210~1340m. The area is composed of intermediate-acid eruptive rocks, and the regional structure is relatively stable. The lithology of the stratum is mainly claystone, basalt and gravel soil. The overburden layer is thin and has no water storage conditions. The type of groundwater is mainly bedrock fissure diving, with insufficient replenishment and small water volume. It is not corrosive to concrete and weakly corrosive to steel structures.

I  Project Features:

1. Environmental characteristics of construction site:

1.1) The foundation rock is in good condition and is made of natural building materials. The building (construction) foundations such as inverters and box transformers can be made from local materials, and the groundwater level is relatively deep, which has no effect on the building foundation.

1.2) Ground leveling and backfilling materials are taken on-site, each layer thickness is less than 0.3m, the soil backfill compaction degree is not less than 0.95, and the gravel backfill compaction coefficient is not less than 0.90. Ensure that the laying surface is smooth and compacted in layers.

1.3) The slope of the foundation pit formed during the construction of the project shall be supported by measures to avoid collapse.

2. Design features of components and inverters:

2.1) The azimuth angle of the photovoltaic modules is arranged due to the south, and the installation inclination angle of the array bracket is 38°. There is no shade of sunlight, and the distance between the lower edge of the photovoltaic panel and the ground after the field level is not less than 40cm. The distance between the brackets is not more than 8m. The inclination angle satisfies the adjustable range of 30°～40°.

2.2) The pile foundation system includes screw piles and adjustable columns. The connection between the column and the foundation connector adopts the bolt penetration connection form. The column system can adjust the height difference in the height direction to ±400mm, and the adjustment range is stepless adjustment.

2.3) Column and component steel are carbon steel, hot-dip galvanized anti-rust treatment, the average thickness is not less than 85μm, to prevent long-term rust and rot.

3. Project construction features:

The construction area is scattered and is dubbed by the industry as "the largest decentralized power station in the country", with gullies and cliffs standing vertically and horizontally. The maximum interval between mechanical allocation and material sorting is more than 20 kilometers, which makes organization and management difficult.

3.1) Independent research and development of chute technology solves the problem of inverted concrete in mountainous areas and realizes continuous pumping and pouring of concrete.

3.2) Material sorting is carried out by adopting the sliding rail technology of secondary transportation, which facilitates the transportation of materials on the construction site, speeds up the construction progress, and saves costs.

3.3) The stratum structure is complex and the lithology is different, the slope is steep, and the construction machinery is difficult to walk. Use a towed drill or a handheld equipment drill to make the hole. Comprehensive use of multiple basic forms.

3.4) Use GPS RTK technology and basic point conversion technology to complete the construction line work accurately and quickly.