龙家山堤防工程复合灌浆新工艺及渗控优化研究

Study on new compound grouting technology and seepage control optimization of Longjiashan embankment project

龙家山水电站库区一段堤防工程,堤内直接挡水,堤外承担防护;堤基为古河床冲击层,深厚强透水砂卵砾石分布不均,堤身为中等透水的素填土、砂层;防护区内渗漏问题严重,常规防渗措施处理难度大、成本高。为减少堤防渗漏并改善堤身的渗透稳定性,通过现场试验研究,提出复合灌浆新工艺对堤防进行防渗处理。通过对堤防进行三维有限元模拟,分析灌浆前后堤防渗流场分布特征,比较分析渗漏量及物探成果,优化提防灌浆防渗工程。研究表明,龙家山堤防自然条件下渗漏问题严重;复合灌浆新工艺可有效解决堤防渗漏问题,形成的防渗帷幕对堤防渗流控制效果显著;灌浆防渗工程优化后可大幅减少工程量、节省投资,复合灌浆新工艺可推广应用于类似工程。

A section of levee project in the reservoir area of Longjiashan Hydropower Station is by embankment, which directly retains water inside and bears the protection outside the base of levee,is the impact layer of ancient riverbed with uneven distribution of deep and strong permeable sand and gravel, and the levee body is the medium permeable plain fill soil and sand layer. The leakage problem is serious in the protection zone, and the conventional anti-seepage measures are difficult to preform and too expensive. In order to reduce the leakage of the dike and improve seepage stability, a new composite grouting technique is put forward to prevent seepage of the embankment. A three-dimensional finite element model is established to analyze the distribution characteristics of seepage field in embankment before and after grouting. The results show that the seepage problems of Longjia-shan embankment are serious under the natural condition. The newly presented composite grouting technique can effectively solve the seepage problem of such type of embankment. The optimized grouting and seepage control procedures proposed in this study can dramatically reduce the workload and then save cost. The newly presented composite grouting technique can be used to similar projects.