布达拉宫地基岩体稳定性研究

STUDY ON STABILITY OF FOUNDATION ROCK MASS OF POTALA PALACE

野外地质调查表明,布达拉宫地基岩体岩性为灰黑色角岩化钙质板岩,表层岩体多呈弱风化,局部为强风化;岩体较坚硬完整,基本质量等级分类为Ⅱ～Ⅲ级;岩体的层面、坡面、结构面与临空面的组合关系有利于岩体的稳定性;没有发现岩体产生滑移的现象和证据。X光衍射试验分析表明,布达拉宫基岩中绝大多数为弱膨胀岩,其膨胀性对建筑物地垄墙体不会有太大影响。综合分析表明,布达拉宫地基岩体是稳定的。应该完善布达拉宫的给排水系统,减少地下水对地基岩体稳定性的不利影响。

The stability of foundation rock mass of Potala Palace was studied via field geological investigation, Xray diffraction, engineering geophysical exploration and laboratory mechanics test. Field geological investigation showed that the lithology of rock mass is gray black hornfelsed calcareous slate, the superficial rock mass is mostly slightly weathered and local highly weathered, the rock mass is rather intact solid and its basic quality classification belongs to Ⅱ～Ⅲ, the composite relation between bed plane, slope, structural plane and free surface benefits the stability of rock mass, no phenomena and evidence of the rock mass's gliding was found. Xray diffraction test showed that most rock mass is weak swelled and no effect on the foundation of buildings. Mechanics test proved that the value of rock's parameters including σt,σc,E,μ,C and φ is very high and the rock performance is better. Engineering geophysical exploration indicated that the predominant period of the rock mass is quite different from the selfvibration frequency of the buildings,so the resonance between the rock mass and the buildings don't need to be taken into account. So the foundation rock mass of Potala Palace is stable. The water supply and sewerage system in Potala Palace should be improved to decrease the adverse effect of underground water on the stability of foundation rock mass.