圆明园舍卫城遗址夯土崩解试验研究及保护建议

夯土的工程特性与夯土的抗风化能力息息相关，尤其夯土的矿物构成、颗粒密度和耐崩解性能决定了夯土城墙的稳定性与抗风化能力。本文首先对圆明园舍卫城遗址夯土的矿物成分进行了分析，然后根据土工试验方法等国家标准，对舍卫城夯土含水率、块体密度、开孔孔隙率、颗粒密度、总孔隙率、颗粒粒径进行了测试实验，并并开展了夯土耐崩解性实验。研究结果表明，舍卫城夯土主要由石英、方解石、斜长石、微斜长石、绿泥石，云母等构成。夯土本身富含粘土矿物及夯土颗粒分布级配不良是夯土城墙破坏的重要内因，水是舍卫城夯土城墙破坏的重要外因，而水的来源主要有储存的地下水及毛细作用，以及明显降雨，至夯土墙体饱和，使土体内部产生不均匀应力，导致土体沿着孔隙、裂隙方向崩解。在此研究基础上给予相应的保护建议。

Experimental study on the disintegration of rammed earth and suggestions for its protection at the relics of Sravasti in Old Summer Palace

The engineering characteristics of rammed earth are closely related to its weathering resistance, especially the mineral composition, particle density and disintegration resistance. In this paper, the mineral composition of rammed earth at the relics of Sravasti in Old Summer Palace is analyzed firstly. Then, according to the national standards of soil, the water content, block density, open porosity, particle density, total porosity and particle size of rammed earth in Sravasti are tested, and also the disintegration resistance of rammed earth is tested either. The results show that the rammed earth is mainly composed of quartz, calcite, plagioclase, microcline, chlorite and mica. Rammed earth itself is rich in clay minerals and poor distribution. The grading of rammed earth particles is an important internal cause of rammed earth wall damage. Water is an important external cause of rammed earth wall damage in the Sravasti. The source of water mainly includes stored groundwater and capillary action, as well as obvious rainfall, until the rammed earth wall is saturated, which causes uneven stress in the soil body, leading to the collapse of the soil body along the direction of pores and cracks. On the basis of this study, corresponding protection suggestions are given.