纵向增强体新型土石坝稳定性研究

纵向增强体土石坝具有成本低、施工效率高等优点,尤其适用于病险老坝的整治与改建,或缺少合格黏土心墙料地区新建的中小型坝。但因缺乏设计经验和可借鉴的先例,新坝型在渗流稳定、增强体心墙受力变形、坝坡稳定等方面亟待深入探讨。方田坝水库是国内首例采用纵向增强体土石坝的工程,基于其建立模型,采用有限单元法和有限差分法对其稳定性进行了分析,同时讨论了坝坡坡比的可优化性。研究结果表明:新坝型防渗性能较好;混凝土心墙受力以压应力为主,出现整体性破坏的可能性较小;理论上坝坡坡比有可优化的空间,但仍需要经过工程实践的进一步检验。若坝高较小、坝坡坡比合理且保证施工质量,纵向增强体土石坝稳定性较好。

Stability analysis on the new-type longitudinal reinforced earth-rock fill dam

The longitudinal reinforced earth-rock fill dam has the advantages of low cost and high construction efficiency, which is especially favorable for the reconstruction of old or diseased dams, and for the medium and small dams built in the areas lacking qualified clay materials. Due to the lack of design experience and referential precedents, the new-type dam needs to be discussed in depth in the aspects of seepage stability, stress and deformation of the longitudinal reinforced core wall, and the dam slope stability. The finite element method and finite difference method were used to analyze the stability of the model based on Fangtianba Reservoir, which is the first project adopting this new scheme in China. Meanwhile, the optimization of dam slope gradient of this new-type dam were discussed. The results showed that the seepage prevention effect of this new-type dam is superior, and compressive stress is the major stress on the concrete core wall, and there is less possibility of structural failure. The slope gradient can be optimized theoretically, but needs to be tested by long-term engineering practice. The longitudinal reinforced earth-rock fill dam is stable in the case of the low dam height, reasonable slope gradient and guaranteed construction quality.