Resultant Earth Pressure Research Articles

Distribution of active earth pressure of retaining wall with wall movement of rotation about top

Based on the Coulomb's theory that the earth pressure against the back of a retaining wall is due to the thrust exerted by the sliding wedge of soil from the back of the wall to a plane which passes through the bottom edge of the wall and has an inclination equal to the angle of τ, the theoretical answers to the unit earth pressure, the resultant earth pressure and the point of application of the resultant earth pressure on a retaining wall were obtained for the wall movement mode of rotation about top. The comparisons were made among the formula presented here, the formula for the wall movement mode of translation, the Coulomb's formula and some experimental observations. It is demonstrated that the magnitudes of the resultant earth pressures for the wall movement mode of rotation about top is equal to that determined by the formula for the wall movement mode of translation and the Coulomb's theory. But the distribution of the earth pressure and the points of application of the resultant earth pressures have significant difference.

Researches on earth pressure about cantilever wall with cohesive soil as backfill : Fukuoka, M; Yoshida, Y J Fac Engng Univ Tokyo, Ser B, V33, N2, 1975, P105–122

In order to measure the earth pressure and wall friction acting on the entire faces of a T type steel retaining wall, a new method by using measuring panels and load cells was developed, enabling to obtain the magnitudes of the resultant earth pressure acting on the vertical wall and base plate of the retaining wall. It was clarified that wall friction acts on the vertical wall and the upper side of the base plate even when the backfill surface is flat. The wall friction disturbs the principal stress lines from the vertical wall for the distance almost equivalent to the height of the retaining wall. In the portion sufficiently apart from the vertical wall, the ratio of vertical pressure to horizontal earth pressure is determined by the Poisson's ratio and deformation coefficient of soil. The result shows a quite big difference from Coulomb, Terzaghi and Peck.

Experimental Study on Earth Pressure of Retaining Wall by Field Tests

The characteristics of the earth pressure acting on a retaining wall are investigated on the basis of the large scale prototype tests in a field. The wall is made of concrete and 10 M in height. The silty sand and the slags are used as the backfill materials. The measured earth pressure at rest and change to the earth pressure in the active and passive states are shown. The influence of displacement of the wall on the magnitude and the distribution of earth pressure in the vertical direction are shown and discussed. The co-efficient of earth pressure, the angle of wall friction and the point of application of resultant earth pressure are also examined. Based on the new informations obtained from the tests, the design philosophy of a retaining wall is considered and it is proposed that a general retaining wall should be designed against the earth pressure at rest. Finally the measured earth pressures are compared with the analyzed results by fem. /Author/TRRL/

Discussion of construction norms: Earth pressure on lock chamber walls

1. Upward deflections of lock chambers in winter (observed everywhere) are the principal cause of additional earth pressure, which considerably increases the active earth pressure according to Kulon. 2. An analysis of lock operations under wintertime conditions shows that standard requirements [11] should be revised to account for chambers undergoing repair, since the calculated load on the wall has increased to passive pressure as determined by Eq. (1) with respect to wall friction. The angle of friction should be considered in accordance with the observed data at 2–5° less than the angle of internal earth friction. 3. The direction of overall resultant earth pressure on the wall as the chamber tends to rise coincides with the direction of the active earth pressure, exceeding it by 2–3 times. 4. The increase in earth pressure on the chamber walls as noted from soil dynamometer readings is, to a considerable extent, compensated for by friction along their rear faces. This causes stresses in calculated cross sections of the walls to increase slightly, but the load on the bottom increases correspondingly, which conforms to the observed data. 5. For unloaded lock chambers (and for wide chambers, dry docks, for example) it is difficult to ensure a standard safety factor against floating. A calculation of passive pressure by Eq. (1) solves this problem and permits one to obtain additional savings from a decrease in the amount of concrete in the chambers and from a more simplified drainage system. 6. Calculation methods for lock chambers constructed as docks, allowing for deformations in the wall and bottom, and earth friction resistance along the rear faces of the walls, gave earth pressure values close to the actual.