研究目的:结合地铁既有50 kg/m钢轨7号单开道岔和60 kg/m钢轨9号单开道岔的结构特征,建立地铁岔枕荷载弯矩的计算模型,分析在移动荷载作用下岔枕荷载弯矩的变化规律,得出相应的岔枕荷载弯矩值。在此基础上,按照我国预应力混凝土轨枕设...研究目的:结合地铁既有50 kg/m钢轨7号单开道岔和60 kg/m钢轨9号单开道岔的结构特征,建立地铁岔枕荷载弯矩的计算模型,分析在移动荷载作用下岔枕荷载弯矩的变化规律,得出相应的岔枕荷载弯矩值。在此基础上,按照我国预应力混凝土轨枕设计方法,开展地铁用混凝土岔枕的设计、试验研究工作,以满足地铁道岔的使用要求。研究结论:(1)预应力混凝土岔枕的设计承载正、负弯矩分别为18.8 k N·m和16.7 k N·m,满足设计要求;(2)岔枕截面由预应力产生的混凝土法向应力、设计荷载作用下受压区混凝土压应力均符合标准要求;(3)室内静载抗裂试验和疲劳试验结果均满足承载要求;(4)本文研究对预应力混凝土岔枕的设计具有一定的参考意义。展开更多
The couple effect of soil displacement and axial load on the single inclined pile in cases of surcharge load and uniform soil movement is discussed in detail with the methods of full-scale field tests and finite eleme...The couple effect of soil displacement and axial load on the single inclined pile in cases of surcharge load and uniform soil movement is discussed in detail with the methods of full-scale field tests and finite element method. Parametric analyses including the degree of inclination and the distance between soil and pile are carried out herein. When the displacement of soil on the left side and right side of a pile is identical, deformation of a vertical pile and an inclined pile is highly close in both cases of surcharge load and uniform soil movement. When the couple effect of soil displacement and axial load occurs, settlement of an inclined pile is greater than that of a vertical pile under the same axial load, and bearing capacity of an inclined pile is smaller than that of a vertical pile. This is quite different from the case when the inclined pile is not affected by soil displacement. For inclined piles, P-Δ effect of axial load would lead to a large increase in bending moment, however, for the vertical pile, P-Δ effect of axial load can be neglected. Although the direction of inclination of piles is reverse, deformation of piles caused by uniform soil movement is totally the same. For the inclined piles discussed herein, bending moment(-8 m to-17 m under the ground) relies heavily on uniform soil movement and does not change during the process of applying axial load. When the thickness of soil is less than the pile length, the greater the thickness of soil, the larger the bending moment at lower part of the inclined pile. When the thickness of soil is larger than the pile length, bending moment at lower part of the inclined pile is zero.展开更多
文摘研究目的:结合地铁既有50 kg/m钢轨7号单开道岔和60 kg/m钢轨9号单开道岔的结构特征,建立地铁岔枕荷载弯矩的计算模型,分析在移动荷载作用下岔枕荷载弯矩的变化规律,得出相应的岔枕荷载弯矩值。在此基础上,按照我国预应力混凝土轨枕设计方法,开展地铁用混凝土岔枕的设计、试验研究工作,以满足地铁道岔的使用要求。研究结论:(1)预应力混凝土岔枕的设计承载正、负弯矩分别为18.8 k N·m和16.7 k N·m,满足设计要求;(2)岔枕截面由预应力产生的混凝土法向应力、设计荷载作用下受压区混凝土压应力均符合标准要求;(3)室内静载抗裂试验和疲劳试验结果均满足承载要求;(4)本文研究对预应力混凝土岔枕的设计具有一定的参考意义。
基金Project(51208071)supported by the National Natural Science Foundation of ChinaProject(2010CB732106)supported by the National Basic Research Program of China
文摘The couple effect of soil displacement and axial load on the single inclined pile in cases of surcharge load and uniform soil movement is discussed in detail with the methods of full-scale field tests and finite element method. Parametric analyses including the degree of inclination and the distance between soil and pile are carried out herein. When the displacement of soil on the left side and right side of a pile is identical, deformation of a vertical pile and an inclined pile is highly close in both cases of surcharge load and uniform soil movement. When the couple effect of soil displacement and axial load occurs, settlement of an inclined pile is greater than that of a vertical pile under the same axial load, and bearing capacity of an inclined pile is smaller than that of a vertical pile. This is quite different from the case when the inclined pile is not affected by soil displacement. For inclined piles, P-Δ effect of axial load would lead to a large increase in bending moment, however, for the vertical pile, P-Δ effect of axial load can be neglected. Although the direction of inclination of piles is reverse, deformation of piles caused by uniform soil movement is totally the same. For the inclined piles discussed herein, bending moment(-8 m to-17 m under the ground) relies heavily on uniform soil movement and does not change during the process of applying axial load. When the thickness of soil is less than the pile length, the greater the thickness of soil, the larger the bending moment at lower part of the inclined pile. When the thickness of soil is larger than the pile length, bending moment at lower part of the inclined pile is zero.
