Caption: Figure 11: Distribution of lateral pressure
on the left wall of section I.
 to determine the lateral pressures
on rigid nonyielding retaining walls with geofoam inclusion for various wall heights and EPS panel thickness of t = 1.2 m by using finite element software Sigma/W (GEO-SLOPE International Ltd., 2008) showed that specific combinations of geofoam panel thickness and retaining wall height may induce plastic strains in the geofoam.
Therefore, determining the lateral pressure
coefficients [[lambda].sub.x] and [[lambda].sub.y] of the initial ground field in the tunnel area is important.
To better numerically simulate the in situ stress field of the Ertan hydropower station, two lateral pressure
coefficients, 1.5 and 2.5, are both considered.
According to the equation mentioned above, compressive strength of the element lateral pressure
will be obtained:
In centrally compressed concrete elements with confinement reinforcement, in any point of which uniform lateral pressure
is created, the limit stress [[sigma].sub.bzu] can be calculated by formula obtained theoretically in the work 
The reason is that when the wall moves back, no significant change is observed in the induced lateral pressure
This causes circumferential tensile strain and stress in the CFRP sheet, and then the CFRP sheet applies lateral pressure
to the GFRP pipe conversely, which restrains the lateral expansion and longitudinal splitting of the short pipe and heightens its ultimate compressive stress.
The use of geofoam backfilling against a vertical structure significantly reduces and/or eliminates lateral pressure
on that structure, whether it is a bridge abutment, retaining wall, or foundation wall.
It is all too easy to inadvertently overstress the joints or connections--perhaps too much lateral pressure
is applied on a fitting during use, which causes it to break.
Using the ratio, lateral pressure
is simply calculated by the horizontal stress integration.
In such cases, a patient may not suffer from an excessive lateral pressure