摘要
为探究高抗震设防地区粉土路基处治措施的有效性,开展了素粉土路基和加筋粉土路基的振动台模型试验,在对比分析2组模型破坏特征与动响应规律的基础上,探讨了加筋对粉土路基抗震性能的影响机理。研究表明:试验素粉土路基在地震荷载加速度峰值加载到0.25 g后逐渐出现开裂、破碎和沉陷式破坏;在路基边坡侧加入4层土工格栅后,可有效提高粉土路基的抗震能力,当地震荷载加速度峰值加载到0.35 g后加筋粉土路基虽然也出现了裂缝,但路基仍能保持有良好的完整性;地震荷载下加筋粉土路基和素粉土路基具有基本相同的加速度和动土压力响应规律,加速度放大倍数随路基高度的增加而非线性增大、随地震荷载的增加加速度放大倍数增幅减小,相同荷载下路基边坡侧的放大倍数较中心线侧大,但加筋粉土路基的差异较小;2组模型的动土压力均在路基高度方向上呈“两边大,中间小”的形态,在沿路基横断面方向上表现为路基中心线侧的动土压力大于边坡侧;受路基结构影响,地震荷载下加筋粉土路基的潜在破裂面会在加筋体末端和低压实度区内形成;加筋是提高路基抗震性能的有效措施。实际工程应用时筋材长度不应小于0.65H,并还应有足够的锚固长度。
In order to investigate the effectiveness of treatment measures for silt subgrade in high seismic fortification areas,vibration table model tests were conducted on pure silt subgrade and reinforced silt subgrade.Based on a comparative analysis of the failure characteristics and dynamic response laws of the two models,the influence mechanism of reinforcement on the seismic performance of silt subgrade was explored.The experiment shows that after the peak acceleration of seismic load reaches 0.25 g,the experimental pure silt subgrade gradually experiences cracking,fragmentation,and sinking failure.After adding four layers of geogrids on the slope side of the subgrade,the seismic resistance of the silt subgrade can be effectively improved.When the peak acceleration of the seismic load is loaded to 0.35 g,although cracks also appear on the reinforced silt subgrade,the subgrade can still maintain good integrity.Under seismic loads,reinforced silt subgrade and pure silt subgrade have basically the same acceleration and dynamic soil pressure response rules.The acceleration amplification factor increases nonlinearly with the increase of subgrade height,and decreases with the increase of seismic load.Under the same load,the amplification factor on the slope side of the subgrade is larger than that on the centerline side,but the difference between reinforced silt subgrade is smaller.The dynamic soil pressure of both models shows a pattern of“larger on both sides and smaller in the middle”in the height direction of the subgrade.In the direction of the subgrade cross-section,the dynamic soil pressure on the centerline side of the subgrade is greater than that on the slope side.Due to the influence of subgrade structure,the potential fracture surface of reinforced silt subgrade under seismic loads will form at the end of the reinforced body and within the low pressure compaction zone.Reinforcement is an effective measure to improve the seismic performance of silt subgrades.In practical engineering applications,the length of the reinforcement should not be less than 0.65 H,and there should also be sufficient anchoring length.
作者
刘泽
罗佳晔
严文钦
黄振华
LIU Ze;LUO Jiaye;YAN Wenqin;HUANG Zhenhua(School of Civil Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;School of Geosciences and Info-physics,Central South University,Changsha 410012,China)
出处
《地震工程与工程振动》
北大核心
2025年第4期116-125,共10页
Earthquake Engineering and Engineering Dynamics
基金
湖南省自然科学基金项目(2022JJ20357)
湖南省教育厅重点科研项目(23A0368)。
关键词
粉土路基
加筋
振动台试验
动响应特性
潜在破裂面
silt subgrade
reinforcement
shaking table test
dynamic response characteristics
potential fracture surface
