定向钢纤维pcc桩水平承载特性试验研究.doc

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摘  要

现浇混凝土薄壁管桩（简称PCC桩）是由河海大学岩土工程科学研究所研发的一种新型桩型。钢纤维混凝土是在普通混凝土中掺入不定向分布的钢纤维以增强混凝土力学性能的新型复合材料。本文采用钢纤维混凝土材料和PCC桩型，通过模型试验探究定向钢纤维PCC桩的水平承载特性，本文的主要工作和结论包括： 

1、设计了定向钢纤维PCC桩模型试验方案，利用通电螺线圈内产生单向磁场的原理，制作了定向钢纤维PCC模型桩。结果表明：通过通电线圈护筒，可以将混凝土中随机分布的纤维实现定向分布，为实际工程中实现定向钢纤维PCC桩提供了技术思路。

2、开展了定向钢纤维PCC桩水平承载特性试验，得到桩顶水平位移—荷载曲线和桩顶水平位移梯度—荷载曲线，确定了单桩的水平承载力。

3、通过控制掺量和定向两个参数，开展多组对比试验。试验结果表明：在相同掺量下，定向钢纤维PCC桩比不定向纤维PCC桩水平承载力提高10%~20%；在一定掺量范围内，定向钢纤维PCC桩的水平承载力随钢纤维掺入量增加而提高。

关键词： 定向钢纤维；PCC桩；水平承载；模型试验研究 

         

ABSTRACT

The cast-in-situ concrete thin-wall pipe pile (simple named PCC) is a new type of pile, developed by the Research Institute of Geotechnical Engineering of Hohai University. Steel fiber concrete is a new composite material which is incorporated into non-oriented steel fiber in normal concrete, in order to enhance mechanical properties of concrete. It’s the material of steel fiber concrete and the type of PCC pile that are used in this paper. The behaviors of the oriented steel fiber reinforced PCC pile, which subjected to lateral load have been studied in the physical model test. The main contents and conclusions are as follow：

1、Designing model test of oriented steel fiber reinforced PCC pile is used to instruct making the model of oriented steel fiber reinforced PCC pile. It’s made on the basis of principle that energizing solenoid produces oriented magnetic field. The results show that: it’s the oriented magnetic field produced by energizing solenoid that makes  the idea come true, which is that the steel fiber becomes oriented in the concrete. It provides technical ideas on oriented steel fiber reinforced PCC pile used in engineering practice.

2、The purpose of developing test study, which is on behaviors of oriented steel fiber reinforced PCC pile under lateral load, is to draw the curve of  and the curve of  , determining horizontal bearing capacity of single pile. 

3、By controlling two parameters of mixing amount and orientation, multiple sets of comparative tests have been carried out. As the test results show, the horizontal bearing capacity of oriented steel fiber reinforced PCC pile has increased by 10% to 20%, compared with non-oriented steel fiber reinforced PCC pile at the same mixing amount. In certain extent of mixing amount, horizontal bearing capacity of oriented steel fiber reinforced PCC pile will be increased with the addition of mixing amount.

Key words: oriented steel fiber；Cast-in-situ concrete thin-wall pipe pile；lateral load；model test study