I  Project Overview

1. Project Introduction：

The 50MW photovoltaic power station project in Baoguping, Butuo County, Sichuan is a poverty alleviation project developed and implemented by the local government to solve local electricity demand, develop the economy, and actively develop new energy sources, combining local geological conditions and sunlight conditions.The whole project adopts a longitudinal purlin and a horizontal support arrangement plan. The support is composed of steel pipe columns, steel beams, diagonal braces and inter-column supports. The tilt angle of the support is 30°C.

2. Construction Geological Conditions：

The project is located on the south-facing slope of the ridge on the southwest side of Baoguping Township. The altitude is between 3553m-3750m. It is mainly mountainous. The stratum is mainly composed of dissolution depressions, dissolution grooves, stone buds and karst caves. Limestone is exposed in the site. It is extremely prone to undesirable problems such as collapse, shallow landslides, and surface gullies. The large surface of the ground is exposed to mixed crushed stone, silty clay and clay-containing crushed stone, with many karst fissures and occasional caves. The dissolution fracture zone is small in scale and filled with cohesive soil. The region belongs to the "very rich belt" of solar energy resources. The area has strong sunlight in summer and weak in winter; strong at noon and weak in morning and evening.

I  Project Features:

1. There is seasonal frozen soil at the site in winter, coupled with uneven cover thickness and fragmented stone content, uneven distribution of foundation soil. Therefore, the component and building foundation use the method of microporous cast-in-place piles, and measures such as replacement or enlargement of the foundation depth and width are taken. The component foundation on the red clay layer is buried to 1.8m deep. The ground or foundation pit is excavated to form a combined soil and rock foundation, and measures such as replacement, cushion layer, foundation width adjustment and settlement joints are adopted.

2. Karst funnels, karst caves and gullies are all over the site, in order to avoid the damage to the components and equipment caused by slope debris flow and dangerous rock collapse:

2.1) The small gullies increase the buried depth of the foundation, and the large gullies take effective drainage measures;

2.2) Photovoltaic panels and inverters should be placed in areas with high terrain such as ridges and a certain safe distance from the ridges and cliffs. The solar panel arrays are arranged along the slopes, ridges and tops of the mountains, and avoid them. distance.

2.3) Karst has limited impact on the overall stability of the site. Measures such as avoiding dissolution of negative terrain or funnel area, or foundation soil treatment can be adopted to avoid or reduce its impact on buildings. If small caves are encountered during the construction process, they shall be backfilled with rubble concrete.

2.4) When the foundation encounters a small cavity with a small opening, it is advisable to dig out the soft filling material and backfill with crushed stone, block stone, plain concrete or lime soil to enhance the strength and integrity of the foundation. If necessary, a span can be added. In case of large openings, beams, slabs or arches should be used to span.

3. The roads in the station are mainly arranged along the contour lines, and the sections with high terrain and good surface drainage should be selected, and drainage measures such as retaining walls should be constructed. Use slope rate method or retaining wall and other engineering measures to control to avoid scouring and collapse during heavy rain

4. The construction of the project has caused a certain degree of damage to the site environment. The construction of the site should reasonably pile up spoil, avoid areas with large water catchments or take drainage measures to protect vegetation, and restore the construction wound area as much as possible. vegetation.

5. Strengthen the service of workers after construction, and conduct construction survey if necessary.