中文摘要：

敦煌莫高窟北区岩体长期以来在特殊的地形地貌、气象水文、岩土性质、地质构造条件下，受人工开挖、重力、风蚀、雨蚀和洪水冲刷等共同作用，岩体发生风化、卸荷等变异以及崩塌、坍塌和危岩、开裂与裂隙（构造裂隙、卸荷裂隙）等多种变形，严重影响岩体的稳定和洞窟的安全。针对上述变异、变形破坏情况，采用PS材料加粉煤灰浆液灌浆封闭裂隙和岩面喷浆加固相结合的修复方法，有效地防止了岩体变异的进一步扩展和表面风化的加剧，减少了岩体变形和表面风化程度，使石窟得以保护和修复。该方法对黄土及干旱地区石窟保护具有良好的借鉴作用。

英文摘要：

Under the influence of geomorphology, climate and hydrology, rock and soil characteristics, local geology and so on, the rock masses forming the northern Mogao Grottoes in Dunhuang have formed several types of variations and deformations. The variations include surface weathering and load discharging. The deformations contain rock fall, crag and collapse, split and crannies （ structural cranny, discharged cranny, horizontal cranny and vertical cranny） due to artificial digging, gravity, wind erosion, rain erosion and flood erosion. These variations and deformations have generated great dangers to grotto safety and stability of the rock mass. Using potassium silicate material and coal ashes, the crannies are grouted and the surface weathering layers are sprayed. The variations and deformations of the rock masses and surface weathering have been decreased. The rock masses are reinforced and the grottoes are well protected. The method is an effective reinforcement countermeasure for cultural relic protection in the loess and arid region.