挤扩多分支承力盘混凝土灌注桩的应用研究

本文论述的挤扩多分支承力盘混凝土灌注桩是 1998年国家火炬计划重点推广的新兴项目。因其经济、适用、安全、稳定性好而正为众多的公路专家人事看好并广泛应用着。本文就其受力原理、特点及优点、适用范围、计算比较。

整体硬质合金精密高效直槽扩挤刀

扩挤刀是汽车发动机高精度孔加工专用刀具。汽车发动机的进气管是发动机的重要部件，进气管喷油嘴孔的加工质量直接影响汽车的节油性能。过去加工喷油嘴孔大都使用国外进口的精密扩挤刀，价格昂贵，加工成本很高。为了降低加工成本，提高产品的市场竞争力，汽车刀具国产化...

Force analysis and experimental study of pure aluminum and Al-5%Ti-1%B alloy continuous expansion extrusion forming process

The deformation zone of CONFORM extrusion was divided into primary gripping zone,gripping zone,conical expansion chamber zone,cylindrical zone and sizing zone of die,and corresponding force equilibrium equations were established using the Slab method.The deformation force formulae of CONFORM machine at any wrapping angle with an expansion chamber were obtained.Experiment on pure aluminum and Al-5%Ti-1%B alloy was conducted on the CONFORM machine self-designed.The resistance to deformation of Al-5%Ti-1%B alloy at the deformation temperature of 400℃ and the strain rate of 3.07 s-1 was measured to be 50 MPa using Gleeble-1500 thermal simulation machine.The calculation results of deformation forces for CONFORM process with an expansion chamber for pure aluminum and Al-5%Ti-1%B alloy were given.The experimental CONFORM radial force is in agreement with the radial force obtained by theoretical formula.

Extrusion force analysis of aluminum pipe fabricated by CASTEX using expansion combination die

To determine the extrusion force of pipe fabricated by continuous casting and extrusion (CASTEX) using an expansion combination die, the metallic expansion combination die was divided into diversion zone, expansion zone, flow dividing zone, welding chamber, and sizing zone, and the corresponding stress formulae in various zones were established using the slab method. The deformation zones of CASTEX groove were divided into liquid and semisolid zone, solid primary gripping zone, and solid gripping zone, and the formulae of pipe extrusion forces were established. Experiments were carried out on the self-designed CASTEX machine to obtain the aluminum pipe and measure its extrusion force using the expansion combination die. The experimental results of radial extrusion force for aluminum pipe are in good agreement with the calculated ones.

Torsional dynamic response of tapered pile considering compaction effect and stress diffusion effect

Considering both the compaction effect of pile surrounding soil and the stress diffusion effect of pile end soil,this paper theoretically investigates the torsional vibration characteristics of tapered pile.Utilizing the complex stiffness transfer model to simulate compaction effect and tapered fictitious soil pile model to simulate stress diffusion,the analytical solution for the torsional impedance at tapered pile top is obtained by virtue of Laplace transform technique and impedance transfer method.Based on the present solution,a parametric study is conducted to investigate the rationality of the present solution and the influence of soil and pile properties on the torsional vibration characteristics of tapered pile embedded in layered soil.The results show that,both the compaction effect and stress diffusion effect have significant influence on the torsional vibration characteristics of tapered pile,and these two factors should be considered during the dynamic design of pile foundation.

浅谈挤扩支盘灌注桩技术的特点和施工工艺

1 前言挤扩支盘灌注桩,又称"多级扩盘桩""多支盘钻孔灌注桩"、"挤扩多支盘 DX 灌注桩"或简称"DX"桩,是在等截面钻孔灌注桩基础上发展起来的一种新型桩。自1992年在工程中首次使用后,近年来已迅速发展应用效果良好。2 挤扩支盘灌注桩的特点和优点挤扩多分支承力盘混凝土灌注桩由主桩、底盘、中盘、顶盘及数个分支所组成。根据地质情况在硬土层中设置分支及承力盘。支盘桩通过液压挤扩。