厚淤泥地层灌注桩水化温度与承载特性实测分析

Field Monitoring of Hydration Temperature and Bearing Capacity of Cast-in-place Pile in Thick Silt Stratum

钻孔灌注桩的荷载传递机制是粤港澳大湾区岩土工程研究的热点之一,基于现场实测的手段开展了珠海横琴沿海深厚淤泥地层中钻孔灌注桩水化温度与承载特性的实测研究。结果表明:厚淤泥地层中大直径灌注桩早龄期温度在浇筑后31 h内持续升温,最高可达65.3℃,且同一时刻越深位置温度数值越低,水化温度场呈现出自上而下矢量方向的放热热流。早龄期灌注桩钢筋计轴力定量数值介于4~-10 kN以内,受力较小。进一步实测获得了厚淤泥地层灌注桩静载压缩变形陡降型特征,尽管桩基承载力满足设计要求,但沉降位移偏大,桩体发生了刺入变形。分析认为与孔底沉渣处理效果欠妥有关,由此提出大湾区厚淤泥地层中灌注桩施工应注意沉渣处理等质量控制措施。

The load transfer mechanism of cast-in-place bored pile is one of the hot spots in the geotechnical engineering research of Guangdong-Hong Kong-Macao Greater Bay Area.Based on the field monitoring study,this paper carried out the experimental research on the hydration temperature and bearing capacity of cast-in-place bored pile in the deep silt stratum in coastal area of Zhuhai.The results show that,the temperature of large-diameter cast-in-place pile at early age in thick silt stratum continues to rise within 31 hours after pouring,and the highest temperature can reach 65.3℃,and the deeper the position is,the lower the temperature is at the same time,and the hydration temperature field presents a vector direction of exothermic heat flow from top to bottom.The axial force value of reinforcement meter in early age is within 4~-10 kN,and this value is very small.The results show that although the bearing capacity of pile foundation meets the design requirements,the settlement displacement is still too large,and the pile has a penetration deformation.The analysis shows that it has something to do with the poor treatment effect of bottom sediment,so the quality control measures such as sediment treatment should be paid attention to in the construction of cast-in-place pile in thick silt stratum are put forward.