I  Project Overview

1. Project Introduction：

The project belongs to a large-scale ground photovoltaic grid-connected power generation system. It makes full use of the mountain resources of Quyang County to build the "China's largest hillside centralized photovoltaic power station" mountain photovoltaic project with a total installed capacity of 50MW and an overall construction period of 70 days.

2. Construction Geological Conditions：

It is located in the transition zone from Taihang Mountain to the North China Plain. The slope of the mountain is steep, with a maximum slope of over 38°. More than 80% of it is exposed limestone, strongly weathered, and moderately weathered rocks. The structure is loose and easily collapsed. The vegetation coverage rate is less than 20%. The site has a continental monsoon climate with sufficient sunshine throughout the year.

I  Project Features:

1. Environmental characteristics of the construction site:

Combined with its complex terrain and large-area exposed rock formation conditions, in this project:

1.1) According to the geological conditions, the spiral pile foundation is adopted and the conventional construction technology is improved. For areas where direct screw drilling is difficult, a small diameter down-the-hole hammer is used to drill the hole, and then screw drilling is performed on this basis.

1.2) On the foundation of the microporous cast-in-place pile, put steel pipes as reinforcement,and then pour concrete into piles.This kind of technology is widely used in various rock mountain power stations, and the technology is mature and reliable;

2. Design features of components and inverters:

2.1) The photovoltaic array is arranged facing south, and the installation angle of the array bracket is 38°.

2.2) The photovoltaic support is designed in the form of plug-in connection, double hoop, etc., with a height-adjustable function to adapt to the natural conditions of the undulating terrain;

2.3) The column adopts the support arrangement scheme that follows the slope, and the single column scheme is adopted for the areas with slow slope, which reduces the amount of support construction and saves the construction period;

3. Project construction characteristics:

Difficulties such as scattered construction areas, vertical and horizontal ravines, steep slopes, long distances between mechanical deployment and material sorting, and difficulties in organization and management:

3.1) The chute technology is used to solve the inversion of concrete in mountainous areas and realize continuous pumping and pouring of concrete.

3.2) Material sorting is carried out by using the slide rail technology of the secondary transportation, which facilitates the transportation of materials at the construction site, shortens the secondary transportation time to one third of the original, speeds up the construction progress and saves costs.

3.3) The stratum structure is complex and the lithology is different, and various construction machines are difficult to walk. The method of pulling the drill or the handheld device is used to form the hole, and the multiple foundation forms are comprehensively used.

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

3.5) Pile up the spoil on the upper part of the slope to ensure the stability of the slope. When piling up the spoil in the gully or along the riverside, it should prevent the mountain flood from causing debris flow or blocking the river.

3.6) Part of the ground needs to be leveled and backfilled and compacted in layers. The thickness of each layer is less than 0.3m, the compaction degree is not less than 0.95, and the gravel compaction is not less than 0.90. Remove tree roots, weeds and sharp rocks,make laying surface smooth and compacted in layers.