Geocell Reinforcement and Soil Bearing Capacity

Laboratory scale loading tests were conducted on unpaved road test sections to evaluate the influence of lime stabilization and geocell (with 4 different geocell heights) reinforcement on increasing soil bearing capacity. [9]

It was found that short geocells with a large aperture size enhance the settlement of the unbounded granular layer more effectively at low level loads of less than 200 kPa.

Strength

A 3″ Depth Geocell can hold up to 8,000 lbs, ideal for driveways and overflow parking areas. The 6″ Depth Geocell holds up to 80,000 lbs, suitable for commercial applications and heavy-duty infrastructure projects.

Geocells have a higher axial stiffness than conventional geogrids, which is Height Geocell the result of the geometry and the strength of the perforated strip and seam weld. The tensile strength and strain at rupture of the geocell can be determined by using an extensometer.

When the geocell layer is closer to the soil, the shear strength increases up to 31% compared to when the shear strength of the soil is tangential with the edge of the geocell. However, when the failure plane passes through the middle of the geocell height, only a 4% increment is achieved.

Moreover, it is also found that the vertical stress distribution patterns in the geocell mattress are well redistributed and transmit little pressure to the subsoil, which contributes to its good confinement effect. In addition, a higher ratio of height to diameter of the geocell, referred to as aspect ratio, improves the benefit of the reinforcement. This is mainly because the smaller cell opening diameter will increase interfacial shear strength between the soil and the geocell. Hence, a more uniform shear stress distribution will be created in the soil.

Resilience

During loading, soil inside the geocell is compressed and pushes against the cell wall. This develops an additional confining stress along the cell wall that prevents soil lateral displacement [5,8,9]. Therefore, the 3D honeycomb-like network of geocell confines the infill material and resists car rutting by keeping it compacted within its cells. The geocells also redistribute the external load across a larger area and reduce the stresses acting on the underlying soil bed.

In the tests with separated geocell layers, the shear strength of the soil increased by up to 31% due to the smaller pocket opening diameter. The increase in shear strength value decremented with the distance of the geocell layer from the failure plane. When the failure plane passed exactly through the middle of the geocell height, the shear strength increased by 11% compared to the state whereby the edge of geocell is tangential with the failure plane.

Laboratory scale testing was performed on a clayey soil with different lime contents and geocell heights to study the effects of each factor on increasing the bearing capacity of the soil. The experiments were conducted in a steel box with inner dimensions of 1.2 m long, 1.2 m wide, and 1.2 m high. A total of eight unpaved road test sections were made inside the box. The influence of the lime stabilization (3 different lime contents) and the geocell (4 different geocell heights) on increasing the bearing capacity of the soil was studied.

Flexural Stiffness

Haisan Geocell is an innovative geosynthetic which can be used for a wide variety of applications. It is a unique construction with a high rate of stiffness and flexural strength. It consists of two HDPE sheets which are strengthened with high-power ultrasonic welding and then molded into a three-dimensional honeycomb formation. It can be filled with soil, macadam, concrete, or any other granular material. Its asymmetrical design allows for easy installation, and it is designed to handle high stresses without cracking or failure.

The flexural stiffness of a Geocell is a measure of how difficult it is for the structure to bend. It is measured by calculating the stress-horizontal displacement curves using ABAQUS software. This Height Geocell method is able to determine the trends of the shear stress-horizontal displacement curves for each test section and provide an accurate measurement of flexural stiffness.

It is also important to note that the flexural stiffness of the geocell is related to the height of the cell and the size of the pocket opening. A smaller pocket opening size increases the shear strength of the soil by up to 31%. However, if the shear strength is increased to a level which requires an increase of up to 80% in the pocket opening diameter, shear strength increment decreases by around 5%.

The shear strength of the soil and the flexural stiffness of the geocell can be improved by increasing the number of cells in the construction, decreasing the pocket opening size, or both. However, the maximum shear strength of the soil should be limited to a value which is less than the ultimate shear strength of the geocell, in order to prevent local tearing and excessive spreading.

Interfacial Cohesion

In terms of the interfacial cohesion, the height of the geocell can be considered as one of the crucial parameters that influence the reinforcing effect. The higher the geocell height, the more effective the interfacial cohesion is, resulting in a more uniform distribution of the load within the soil mattress. The higher the ratio of the height to the pocket diameter or the aspect ratio, the more significant the effect is.

The modeling results showed that the shear stress-horizontal displacement curves exhibited similar trends to those of the unreinforced soil, but the differences increased with increasing geocell height. This result can be explained by the fact that when a geocell has a high aspect ratio, it tends to offer more confining stresses in its pockets, resulting in improved shear strength at the interface.

In addition, the higher the geocell height, the more it can resist the shear forces and confine the soil particles inside its pockets. As a consequence, the heaving phenomena are controlled, which makes the height of the geocell an important factor in determining its traffic benefit ratio.