§6 Earth Pressure and Retaining Wall 土压力理论与挡土墙设计 Introduction/ 引言 Rankine’s earth pressure theory / 朗肯土压力理论 Coulomb’s earth pressure theory / 库仑土压力理论 Discuss / 讨论 Retaining wall design / 挡土墙设计

6.1 Introduction/ 引言 -Coefficient of earth pressure at rest 主动土压力 被动土压力 静止土压力

6.2 Rankine Earth Pressure theory / 朗肯土压力理论 Limit state/ 极限状态 -Active limit equilibrium/ 主动极限平衡 -Passive limit equilibrium/ 被动极限平衡

6.2.2 Rankine active earth pressure/ 主动土压力 In Non-Cohesive soils (soil surface horizontal)/ 地表水平无粘性土

In Cohesive soils (soil surface horizontal)/ 地表水平粘性土

For sloping soil surface(β) / 地表倾斜

6.2.3 Rankine passive earth pressure/ 被动土压力 In Non-Cohesive soils (soil surface horizontal) / 地表水平无粘性土

In Cohesive soils (soil surface horizontal)/ / 地表水平粘性土

6.3.1Basic concept -Assuming -Active earth pressure 6.3 Coulomb’s Earth Pressure theory / 库仑土压力理论 -Passive earth pressure

6.3.2 Active Case/ 主动情形 General solution

If i=0,α=0,δ=0, Then

Complex boundary conditions/ 复杂边界条件

-Coefficient of active earth pressure / 主动土压力系数 λ a

-Distribution of active earth pressure / 土压力的分布

-Example A retaining wall of embankment is 6m high. And the relative parameters are c=0,φ=30 。,α=14 。 00’,δ=φ/3, as well as shown in Fig. below. Calculate the active earth pressure and draw the distribution.

-Solution ① Assuming sliding surface is BC

② Verifying sliding surface location So, The Sliding surface agrees with the assumption. ③ Calculate the Coefficient of active earth pressure λa ④ Calculate the active earth pressure Ea and its distribution

⑤ Draw the distribution of the active earth pressure

6.3.3 Passive Case

If i=0,α=0,δ=0, Then 6.4 Discuss Equivalent internal friction angle

6.4.2 Several-layer soils

6.4.3 wall back in polygonal line

6.4.4 graphical method

6.4.5 Earth pressure of abutments