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基于空间滑动面(SMP)准则改进的K_0固结各向异性修正剑桥模型,考虑K_0固结饱和黏土初始应力各向异性、应力历史及应力诱发各向异性对土体三维力学特性的影响,推导了静压沉桩柱孔扩张问题的弹塑性解析解。在此基础上,根据桩侧土体应力状态与单剪试验中试样应力状态的相似性,结合桩周土轴对称固结理论提出采用孔压静力触探仪(CPTU)锥尖阻力、锥肩孔隙水压力及相应孔压消散数据预测静压桩时变承载力的理论方法。通过离心机模型试验实测结果和理论预测值的对比,验证了理论方法的有效性,研究了静压桩承载力随时间的变化规律。研究结果表明,本文理论预测方法避免了土体基本参数测定等繁琐过程,且可以较为合理地预测静压桩时变承载力;静压桩沉桩结束后其承载力在短时间内迅速增加,之后承载力增加幅度变缓且逐渐趋于稳定值;静压桩桩径越大,沉桩结束后承载力增加的速度越慢,承载力达到稳定值的时间越长。
The modified K_0 consolidation anisotropy modified Cambridge model based on space sliding surface (SMP) criterion considers the influence of initial stress anisotropy, stress history and stress-induced anisotropy of K_0 consolidated saturated clays on three-dimensional mechanical properties of soils Elasto - Plastic Analytical Solution of Hole Expansion in Static Compression Piles. On this basis, according to the similarity of the stress state of the soil between pile side and the stress state of the specimen in the single-shear test and the axial symmetry consolidation theory of the soil around the pile, the cone tip resistance of the CPTU is proposed, Theoretical Method for Predicting Time - dependent Bearing Capacity of Static Pressure Piles with Cone Shoulder Pore Water Pressure and Corresponding Pore - pressure Dissociation Data. By comparing the measured results of centrifuge model test with theoretical predictions, the validity of the theoretical method is verified, and the variation of bearing capacity of static pile with time is studied. The results show that the theoretical prediction method of this paper avoids the tedious process of determining the basic parameters of soil, and can predict the time-varying bearing capacity of the static pressure pile more reasonably. The bearing capacity of the static pressure pile increases rapidly in a short period of time, After that, the increase of bearing capacity becomes slower and tends to be stable. The larger the diameter of static pile, the slower the increase of bearing capacity after the pile sinking, and the longer the bearing capacity reaches the stable value.