基於振動之重力式擋土牆性能評估技術初探

A PRELIMINARY STUDY ON VIBRATION-BASED PERFORMANCE ASSESSMENT OF GRAVITY RETAINING WALLS

柯永彥(Yung-Yen Ko) ； 黃彥植(Yan-Jhih Huang) ； 高啓津(Chi-Chin Kao)

《中國土木水利工程學刊》 32卷8期 (2020/12) Pp. 755-765

https://doi.org/10.6652/JoCICHE.202012_32(8).0009

摘要

為能在擋土結構性能下降但未達破壞前及時掌握而防患於未然，本研究針對常用之重力式擋土牆，利用其振動反應展現牆－土互制系統之動力特性，以評估其擋土性能；此外，建議基於振動之性能指標，具體量化擋土牆性能變化程度；並利用室內縮尺模型試驗，驗證前述方法之可行性。結果顯示，背填土因降雨濕潤與主動破壞僅造成牆－土系統自然頻率微幅改變，但綜合自然頻率與振動放大係數之損傷指標可反映檔土牆穩定性之下降；牆趾土壤開挖與牆基土壤弱化則對自然頻率有顯著影響，據以估算基礎旋轉阻抗後，可呈現擋土牆基礎抗傾覆性能之降低。

關鍵字

重力式擋土牆 ； 振動量測 ； 性能評估 ； 縮尺模型試驗

並列摘要

In order to detect the degradation of retaining structures before failure is caused so that the follow-up slope disasters can be prevented, this study aims to assess the stabilization performance of the widely used gravity retaining wall based on its vibration response, which can reveal the dynamic characteristics of the wall-soil interaction system. In addition, vibration-based performance indices were suggested to quantify the performance variation of retaining walls. Laboratory scale-model tests were also conducted to examine the feasibility of the proposed methods. Results showed that the moistening of backfill due to simulated rainfalls as well as its active failure caused merely slight change of the natural frequency of the wall-soil system, yet its stability decrease can be reflected using a vulnerability index which incorporate the natural frequency and the amplification factor of vibration. On the other hand, excavation near the toe of the wall and weakening of the soil beneath the foundation significantly influenced the natural frequency, and the rotational stiffness of the foundation can be accordingly estimated to quantify the overturning resistance of the wall.

並列關鍵字

gravity retaining wall ； vibration measurement ； performance assessment ； scale-model test