使用极限状态大圆筒土压力计算方法

Computation of earth pressure on large diameter cylinder under service ultimate state

通过对试验数据的分析 ,发现筒倾斜过程中 ,筒内土体的主动土压力及被动土压力的发育程度与筒内径的大小有密切关系。当筒内径足够大时 ,作用在筒内前、后壁上土压力特征与平面挡土墙基本相同。同时根据沉入式大圆筒倾斜过程中 ,作用在筒外壁上土压力沿筒轴分布有一个拐点的特征 ,提出筒倾斜过程绕泥面以下、筒底以上的筒壁某一点转动 ,转动点的具体位置同筒前土的特性有关。根据转动点的位置可以确定筒壁的位移方向及土压力的分布规律 ,为建立作用在筒壁上土压力的数学模型提供了依据。

According to experimental data,during the inclination process,the development of passive and active earth pressure inside the cylinder is closely related to the inner diameter of cylinder.For the cylinder with enough large inner diameter,the earth pressure distribution on front and back inner sides is similar to that of plane retaining wall.It is found that on outer side of cylinder,there is a bending point in the earth pressure distribution curve along cylinder axis.Based on this characteristic,this paper proposes that the buried large diameter cylinder rotates around a point which is below ground surface and above the bottom of the cylinder during the inclination process.And the location of the point is related to the state of earth pressure on front of cylinder.Direction of displacement and earth pressure of each point on the wall of the cylinder can be determined from the location of the rotation point,which will be used to set up a mathematical model for earth pressure distribution on the cylinder wall.Empirical formulas and distribution law of earth pressure around the circular cylinder are also presented.