良渚水利系统中草裹泥的强度变形试验研究

Study on Strength and Deformation of Grass-Wrapped Silt in Liangzhu Water Conservancy System

为了论证良渚时期广泛采用的草裹泥工艺的科学性和合理性,对单个草裹泥、草裹泥堆砌体开展了无侧限抗压强度试验及大型固结试验。通过试验结果表明:草裹泥的受力变形可分为三个阶段,篾条在草裹泥应变达到20%附近时会发生断裂破坏;草裹泥可有效提升淤泥的强度,单个草裹泥的无侧限抗压强度与通缝堆砌相差不大,但错缝堆砌能明显提高无侧限抗压强度。草裹泥之间的排水层会加速淤泥固结,苇荻草与篾条的挤密及嵌入会导致竖向变形增加;苇荻草与篾条的变形对竖向变形的贡献主要发生在3 h前,随着荷载的增加,大部分变形愈趋近于在前期完成,固结完的草裹泥中淤泥密度要比原状淤泥大2.50%,其粘聚力比原状淤泥大38.7%,摩擦角比原状淤泥大20.5%。

In order to demonstrate the scientificity and rationality of grass-wrapped silt technology widely used in Liangzhu period,unconfined compressive strength test and large-scale consolidation test were carried out on single grass-wrapped silt and grass-wrapped silt stack block.The experimental results show that the deformation of grass-wrapped silt can be divided into three stages,and the strip will be broken when the strain of grass-wrapped silt reaches 20%.The unconfined compressive strength of single grass-wrapped silt is not significantly different from that of open-joint stacking,but the unconfined compressive strength of single grass-wrapped mud can be improved obviously by staggered joint stacking.The drainage layer between grass-wrapped silt will accelerate the consolidation of silt,and the compaction and embedding of reed grass and strip will lead to the increasing of vertical deformation.The contribution of the deformation of reed grass and strip to the vertical deformation mainly occurred 3 hours ago.With the increasing of load,most of the deformation tended to be completed in the early stage,and the density of silt in the consolidated grass-wrapped silt was 2.50% higher than the undisturbed silt.Its cohesion and friction angle are 38.7% and 20.5% higher than the undisturbed silt respectively.