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侯振坤, 唐孟雄, 胡贺松, 刘春林, 苏定立. 考虑塌孔的随钻跟管桩承载性能物理模拟试验研究[J]. 岩土工程学报, 2022, 44(1): 153-162. DOI: 10.11779/CJGE202201015
引用本文: 侯振坤, 唐孟雄, 胡贺松, 刘春林, 苏定立. 考虑塌孔的随钻跟管桩承载性能物理模拟试验研究[J]. 岩土工程学报, 2022, 44(1): 153-162. DOI: 10.11779/CJGE202201015
HOU Zhen-kun, TANG Meng-xiong, HU He-song, LIU Chun-lin, SU Ding-li. Physical model tests on bearing performance drilling with pre-stressed concrete pipe cased pile considering hole collapse[J]. Chinese Journal of Geotechnical Engineering, 2022, 44(1): 153-162. DOI: 10.11779/CJGE202201015
Citation: HOU Zhen-kun, TANG Meng-xiong, HU He-song, LIU Chun-lin, SU Ding-li. Physical model tests on bearing performance drilling with pre-stressed concrete pipe cased pile considering hole collapse[J]. Chinese Journal of Geotechnical Engineering, 2022, 44(1): 153-162. DOI: 10.11779/CJGE202201015

考虑塌孔的随钻跟管桩承载性能物理模拟试验研究

Physical model tests on bearing performance drilling with pre-stressed concrete pipe cased pile considering hole collapse

  • 摘要: 随钻跟管桩(DPC桩)是一种新型的非挤土管桩基础,在钻进—成孔—沉桩的过程中桩侧塌孔会影响桩侧注浆液的流动路径和注浆效果,最终影响桩侧摩阻力的发挥。开展了DPC桩桩侧塌孔条件下的注浆及静载物理模型试验,分析了塌孔对DPC桩承载性能、荷载传递特性、桩侧摩阻力分布规律的影响,定量表征了注浆体的三维几何尺寸和空间点位信息,揭示了塌孔影响桩侧摩阻力发挥的原因。得到如下结论:①桩端未嵌岩的条件下DPC桩的荷载–位移曲线均为陡降型,DPC桩的承载本质属性为端承摩擦桩。②注浆后塌孔所形成的孔洞被浆液充填从而引起桩侧摩阻力增大,坍塌渣土填充桩土–间隙引起注浆液的绕流易造成桩侧摩阻力下降。③塌孔影响了桩–土间隙中浆液的流动规律,改变了桩侧注浆体覆盖桩身的面积和厚度,这是其影响桩侧摩阻力发挥的重要原因;桩侧注浆体的面积与厚度是影响桩侧摩阻力发挥的重要因素;桩侧摩阻力与注浆体体积具有较好的三次函数关系。

     

    Abstract: The drilling with pre-stressed concrete pipe cased pile (Referred to as DPC pile) is a typical non-squeezing soil PHC pipe pile foundation. During the process of its hole drilling, soil dumping and pile sinking, the hole collapse around its pile shaft will affect the flow path and effects of the grouting in the clearance between the DPC pile wall and hole wall, and ultimately affect its skin friction. The physical model and static load tests on the DPC piles are carried out. The load-carrying properties, load transfer characteristics and skin friction distribution characteristics of the DPC piles are analyzed. Three-dimensional geometric size and spatial point information of grouting body for the DPC piles are quantitatively characterized. The essential reason for the skin friction of the DPC piles due to hole collapse is revealed. The following conclusions are drawn: (1) The load-displacement curves of DPC piles are all steep drop types under the conditions of no rock-socketed pile end. The DPC piles are a kind of friction end-bearing ones. (2) After grouting, the collapsed hole is filled with grouting to increase the friction resistance, and the bypass of the slurry in the falling sand area causes the friction resistance to drop. (3) The existence of hole collapse affects the flow law of the groutting in the pile-soil gap, and changes the area and thickness of the pile body covered by the grouting body, which is an important reason for affecting the skin friction. The area and thickness of the grouting body covering the DPC piles are the important factors that affect the skin friction. The skin friction of the DPC piles has a good cubic function relationship with the grouting volume.

     

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