抗滑桩裂纹控制荷载结构设计法及工程应用

Crack Control Design Method of Anti-Slide Pile and Engineering Application

抗滑桩与桥梁桩和普通侧向受荷桩结构设计的区别在于,抗滑桩容许"大位移"和"超配筋"。荷载结构计算法采用10mm为位移容许值,导致抗滑桩工程设计中不能充分发挥"大位移"的抗滑性能。本文结合钢筋混凝土受弯构件力学原理,引入抗滑桩裂缝控制准则,在荷载结构计算法的基础上,用裂纹控制准则替代桩顶水平位移容许值进行抗滑桩设计验算,可最大限度地挖掘抗滑桩的抗滑潜力;推导基于K法的抗滑桩设计验算方法的计算公式,阐述裂纹控制荷载结构法的原理、计算和设计流程;以十堰天水国家高速公路K593+850-K594+070滑坡治理工程为案列,分析了抗滑桩桩顶的水平位移组成和影响因素,并比较了传统设计法与本文阐述方法的优缺点。结果表明:桩顶水平位移主要由锚固段岩土体变形引起,位移由岩土体刚度决定,与桩体设计参数无关,优化桩体设计参数仅能限制由桩身弹塑性变形引起的桩顶水平位移。

The structural design difference among anti-slide piles,bridge piles and ordinary lateral loaded piles is that anti-slide piles allowed larger horizontal displacement and more reinforcement than ordinary piles.The load structure calculation method of the anti-slide piles adopt allowable displacement in 10 mm.This way can＇t fully play resistance capability of a large displacement in the design of anti-slide pile.Using the principles of reinforced concrete flexural members mechanics,the paper introduced of the crack control guidelines.On the basis of the load-structure calculation method,replaced the horizontal displacement control by crack guidelines,it carried out anti-slide piles design checking.This method can be developed to maximize the resistance capacity of anti-slide piles.The formula of anti-slide piles design checking method is derived based on＂K＂method.And the principle,calculation and design process of the crack control design method of anti-slide are described.Taken the project of the K593＋850-K594＋070landslide of the Shiyan-Tianshui highway as an example,the paper analyzed composition and influencing factors of the anti-slide pile with top horizontal,and compared the crack control design method with traditional design methods.