摘要
在桥梁工程位于岩溶地区时,溶洞会降低桩端承载力,加剧桩基沉降,一旦桩基因沉降而发生失稳甚至失效,可能引起桥梁开裂或破坏,威胁公路运输安全。为合理设计桩基参数,保障岩溶区高速公路桥梁桩基的安全,文中结合某工程案例,建立串珠状溶洞-桩基-岩土一体化有限元模型,得到3个桩基在不同桩基长度、直径及弹性模量下桩基沉降量的变化规律。结果表明,溶洞会加剧高速公路桥梁桩基的沉降;桩基沉降量随桩基长度、直径、弹性模量增大而减少;为保障桩基安全,防止桩基沉降量超过最大容许沉降量40 mm,5,6,9号桩基的长度不应小于36.62 m,直径不应小于1.73,1.92,1.79 m,弹性模量不应小于33.47,35.37,34.58 GPa。
When building bridge engineering in karst area,pile foundation will inevitably pass through karst cave.Karst cave reduces the bearing capacity of pile tip and aggravates the settlement of pile foundation.Once the pile is unstable or even fails due to the settlement,it may cause the bridge cracking or damage and threaten the safety of highway transportation.In order to design the parameters of pile foundation reasonably and ensure the safety of highway bridge pile foundation,a beaded karst cave pile foundation geotechnical integrated finite element model is established based on an engineering case,and the variation law of pile foundation settlement under different parameters is obtained,such as the pile length,diameter and elastic modulus of three piles.The results show that karst cave will aggravate the settlement of highway bridge pile foundation,and the settlement of pile foundation decreases with the increase of pile length,pile diameter and elastic modulus of pile foundation.In order to ensure the safety of pile foundation and prevent the settlement of pile foundation from exceeding the maximum allowable settlement of 40 mm,the length of No.5,No.6 and No.9 pile foundation should not be less than 36.62 m,the diameter should not be less than 1.73,1.92 and 1.79 m,and the elastic modulus should not be less than 33.47,35.37 and 34.58 GPa.
作者
秦张越
QIN Zhangyue(Department of Civil Engineering, Southwest Jiaotong University, Chengdu 610036, China)
出处
《交通科技》
2021年第4期17-20,共4页
Transportation Science & Technology
关键词
高速公路
桥梁桩基
串珠状溶洞
沉降量
安全性分析
expressway
bridge pile foundation
string-beaded karst
settlement
safety analysis
