Permeable bricks originated in the Netherlands. At that time, in order to prevent the ground from sinking, the Dutch made a small pavement tile with a width of 100 mm, a length of 200 mm, and a thickness of 50 or 60 mm. A gap of about 2 mm was left between the bricks. In this way, the rain will benefit the rain, and the rain will enter the ground from the gap between the bricks. This was later known as Dutch brick.
After that, the American company Shubuluoco invented a pavement brick with a strong water absorption function. When the brick is filled with water, the water will drain to the ground. However, the drainage rate of this kind of brick is very slow. In the rainy weather, this kind of brick can hardly help. This kind of brick is also called as Shubuluoco pavement brick.
In the 1990s, China presented Shubrokko bricks. Based on the principle of the Shubuluo brick, the technicians of Beijing municipal government invented a kind of pavement brick that is covered with permeable holes and has good water permeability. Rainwater will flow from the small holes in the brick to the ground.
In order to strengthen the compressive and flexural strength of the brick body, technicians use crushed stone as a material to participate in cement and adhesive admixtures so that their water permeability and strength can meet the needs of urban roads. This kind of brick is a permeable brick used on municipal pavement, and the price is relatively cheap compared to ceramic permeable bricks fired with ceramics. The pavement paved with permeable bricks can be seen in Beijing's Chegongzhuang, Gongzhufen, Shijingshan and other places.
So what are the factors for building a sponge city? The sponge city mainly uses six methods of seepage, stagnation, storage, net, use, and drainage, which can absorb and use 70% of the rainfall on the spot. Today, let's talk about the "lag" of important factors in the construction of sponge cities.
Approach 1: The construction of rainwater wetlands uses the principles of species symbiosis, material recycling in the ecosystem, and the principle of harmonious structure and function to collect and purify rainwater collected in rainwater gardens and ecological retention ponds. And it has the characteristics of large buffer capacity, good processing effect, simple technology, low investment, and low operating cost, which is extremely suitable for the use in the construction of sponge cities.
Path two: The construction ecological stay area is a way to use the engineering soil and vegetation to store and manage runoff in shallow water depressions or scenic areas. The management area includes grassland filtration, sand and puddle areas, organic layers or coverings, and cultivated soil And vegetation. The requirements of the ecological stay area on soil and engineering technology are different from those of the rain garden, and the methods are more diverse depending on the location of the site, such as the ecological stay zone and the stay tree pond.
Approach 3: The construction of rainwater ponds, that is, the use of natural or artificial ponds or recesses for rainwater infiltration and supplementation of groundwater, rainwater ponds can effectively reduce the peak runoff. However, the rainwater pond slope protection requires the cultivation of moisture-resistant plants. If the rainwater pond is deep (beyond 60cm), short shrubs must be cultivated around the slope protection to form short hedges to eliminate potential safety hazards. At the same time, the entire rainwater pond system needs to form a microcirculation to prevent water body corruption.
This article is just to introduce bricks and stones, there are other ways to complete the "stagnation", and the unknown may need to be continuously explored in practice.