【摘要】 分析了类土质边坡开挖过程中卸荷裂隙的产生机理,认为工程开挖改变了边坡岩土体的应力状态,使边坡岩土体受到一个指向坡外的侧向附加应力,从而导致了原有裂隙的张开和新裂隙的产生。进行了粉质粘土、粉土及粉砂质泥岩开挖卸荷的离心模型实验,实验结果表明,原有裂隙倾角越大、深度越大、离卸荷面的距离越近,卸荷过程中,裂隙的变形量越大,文中给出了上述因素与裂隙变形量的关系曲线;同时,裂隙变形量受结构面与卸荷方向夹角的影响较为明显,实验得出了岩体卸荷受拉破坏时的变形模量与该夹角的函数关系,分析了裂隙变形量受结构面与卸荷方向夹角的影响。提出了在实际工程中确定卸荷带宽度的方法,并以重庆长江库岸为例证明了该方法的可行性。更多还原

【Abstract】 The occurring mechanism of unloading crannies during excavating soil-like material slopes is analyzed. It is shown that the excavation changes stress in the soil or rock masses,and during the excavation,an extra lateral stress in the direction to the slope surface will act on the slopes. The generation of new crannies and the splaying of existing crannies are attributed to the extra stress. The characteristics of unloading crannies and the influencing factors of their displacements are summarized through centrifugal tests in test chamber about the excavation in silt,clay,and completely weathered mudstone. From the tests,it is concluded that deformations of the existing crannies will increase with the accretion of its obliquity,depth and approaching to unloaded surface. The relations of stretch and obliquity of cranny,deformation modulus and angle to unloading direction of cranny are put forward The method of determining the width of unloading zones is presented for practical engineering projects,and feasibility of the method is proved through an application in the bank of Yangtze River in Chongqing City.更多还原