新型装配式生态防护边坡浅层稳定性研究

Study on shallow stability of new assembled ecological protection slopes

边坡生态防护能使边坡免受雨水侵蚀进而发生失稳,但现有边坡生态防护结构大多采用现浇混凝土、注浆锚杆等,施工繁琐、现场作业时间长。为此,提出了一种由小型伞型锚、预制混凝土坡面防护构件以及预制生态植被层组成的新型装配式生态防护结构,并对其所防护边坡的浅层稳定性开展了研究。首先开展室内模型试验,验证了小型伞型锚的锚固性能;然后根据新型结构的组成和受力特点,推导得到该结构防护下边坡浅层稳定性系数的计算公式,结合丽江机场改扩建工程某边坡,分析锚固力和锚间距等关键参数对边坡浅层稳定性的影响规律;最后基于极限平衡法对不同防护条件下边坡潜在失稳状态进行了数值分析。结果表明:新型装配式生态防护结构坡面锚间距的适宜范围为1.5~2.5 m;相比单纯小型伞型锚支护和单纯格构支护,新型结构既能强化边坡浅层稳定性,还可避免局部破坏,发挥下伏土层强度,进而提高边坡整体稳定性,同时具有施工便捷、安装后即可发挥效用以及易于局部拆换等优势。

Slope ecological protection can protect the slope from rainwater erosion which leads to instability failure.However,in the most of the existing slope ecological protection structures,concrete pouring construction and grouting anchor are used,which are relatively cumbersome and require a long on-site operation time.In response to these problems,a new assembled ecological protection structure is proposed,which consists of small umbrella anchors,assembled concrete slope protection components and assembled ecological vegetation layers.And the shallow stability of the soil slope using new assembled ecological protection structure was studied.Firstly,indoor model tests were conducted to verify the anchoring performance of small umbrella anchors.Secondly,based on the composition and mechanical characteristics of the new protection structure,a formula for the safety factor of shallow stability of the protected slope was derived.Combined with a practical slope in reconstruction and extension project of Lijiang airport,the influence of key factors such as anchor force and anchor spacing on the shallow stability of the slope was analyzed.Finally,based on the limit equilibrium method,a numerical analysis was conducted to study the potential instability states of slopes under different protection conditions.The results showed that the suitable range for the anchor spacing of the new assembled slope protection structure was 1.5~2.5 m,and compared to simple small umbrella anchor support and lattice support,the new assembled ecological protection structure can not only strengthen the shallow stability of the slope,but also avoid local damage,give full play of the strength of the underlying soil layers,and improve the overall stability of slopes.Meanwhile,the new structure has the advantages of convenient construction,taking effective immediately after installation,and easy local demolition and replacement.