Reinforcement Geosynthetics (Geogrid Mat) Application

For the ancients with low technological level and underdeveloped productivity, it was needed to rely on completely natural materials and manual labor to solve corresponding engineering problems such as transportation on soft foundations and dams. This article analyzes and elaborates the correspondence between the antient mechanism and modern geosynthetics from the following aspects.

Soft foundation traffic and reinforced cushion

When transporting on weak soft roads and foundations, problems such as loading capacity, deformation and subsidence are need to be resolved.

1. Records of ancient books

In the "Three Kingdoms" written by Chen Shou, Cao Cao was defeated and went through Huarong Road: "The muddy road was inaccessible ... Then he ordered the soldiers to cover the road with grass then they could finally pass the road."

2. Modern development

Before landing in Normandy, in order to ensure that vehicle and personnel moved freely on the soft sandy beach, the Allies developed an AVRE paving vehicle based on the Churchill tank chassis, which was laid on the basis of thick linen and was reinforced with small branches. (this cushion can be looked as "geotextile").

3. Mechanism analysis

The main mechanism of the above methods can be explained like the formation of a backing plate acting on a weak or loose foundation which could well bear the transport by expanding the stress area, increasing the strength of foundation surface to avoid deformation. Its mechanism is similar to the reinforced cushion which is currently widely used in the engineering filed.
The geosynthetics reinforced cushion is composed of a combination of soil cushion and geosynthetics such as a geogrid mat, geocell, etc., which are layered in the cushion. Compared with common cushions, the tensile and shear properties of reinforced cushions are significantly improved, which effectively prevents the cushions from breaking and shearing damage, and ensures the integrity of the cushions. Meanwhile, the rigidity of the reinforced cushion layer is large, which performs the limitation and homogenization of the soft soil deformation and reduces the amount of settlement.

Hydraulic protection

In order to ensure the safety of channels, especially to reduce the hazards such as flood erosion, it is necessary to strengthen and protect its embankment. This article briefly compares the applications of ancient technology and modern geosynthetics in this regard.

1. Ancient technology

Fascine works is a hydraulic component used in projects such as bank protection, plugging and embankment. It was widely used in the Song Dynasty, and the fascine works coiling technology had become considerably mature. Fascine works has the characteristics of taking materials onsite and fast making. It can not only resist the erosion of the river bank and dam stacks during the flood period, prevent the bank from collapsing, but also is suitable for river closure, water invasion and dam construction, plugging and breaching. It was widely used in river management and flood emergency.

2. Modern technology
Geosynthetics such as geobags, geotubes, soft body mattress, geogrid mats, geocells, grids, geonets, etc. can be used in water conservancy engineering facilities such as protection, reinforcement, flood protection and emergency rescue. Their function principle is to play the role of reinforcement, protection, and separation of geosynthetics. For example, only one phase of the Yangtze River Estuary Regulation project used geosynthetics such as soft body mattress for more than 10 million m2.


 

Reinforced soil technology

Placing geogrid mat and geotextile in the soil to form a force stressing system can improve the overall strength and deformation properties, that is, it reflects the "reinforcement" function of geosynthetics by strengthening the soil. This principle is utilized in natural and traditional architecture, and also has been widely utilized in modern engineering.

1. Reinforced soil structure in nature

The Tang Dynasty poet Bai Juyi wrote: "Several early warbler contends for warming tree, whose fresh swallow pecks spring mud." The swallow nest itself is an embodiment of the technology of reinforced soil. The branches and leaves form the framework of the bird's nest, which are well bonded with the soil to form an integrity. Otherwise, the stiffness and integrity of pure soil or pure branches and leaves will be significantly reduced.

2.Application of natural materials reinforcement in traditional engineering

In the Liangzhu culture water conservancy site, the "grass-wrapped mud" technology was used to fill dams and other facilities; the Great Wall in the Han Dynasty was built with the utilization of red willow reeds as reinforced materials. The technology of applying natural materials to reinforce soil structures has been passed down to current day and is continuously used in some fields.

3. Modern reinforced soil technology

Reinforced soil retaining walls utilize geogrid mat as reinforced material and wrapped panel. The research and application of reinforced soil technology is becoming more and more extensive, and has broad development prospects.