基于低應變檢測法的缺陷樁基動力響應研究

中圖分類號：TQ178;TP391.9 文獻標志碼：A文章編號：1001-5922（2025）07-0064-04

Abstract：Relying on a reconstruction project in Chengde High-tech Zone，the dynamic response of the defective pile foundation（necking）underlow straindynamic load was studied byusing the methodofcombining field measurementand three-dimensional dynamic finite element numerical simulation，and the results showed thatthedynamicresponseof themissng pile foundation（necking）changed significantlyunder theactionof the low-strain dynamic detection wave，and the amplitude of the reflected wave increased by about 25% for every O.4 m increase in the necking thickness，and there was no significant change in the reflected wave atthe botom of the pile.For every 0. ^2m increase in pile diameter in the necking area，the amplitude of the reflected wave in the necking area increased by about 10% . The amplitude of the reflected wave at the bottom of the pile increased by about 8% .For every2 m increase in the distance between the necking areaand the topof the pile，the amplitude ofthe reflected wave increased byabout 13% ，and there was no significant change in the reflected wave at the bottom of the pile.When detecting pile foundation defects with low strain dynamics，underthecondition of ensuring thattheexcitation force and action area remain unchanged，attention should bepaid toobservingthe changes inthe necking area and theamplitude of the emission wave at the botom of the pile，so as to beter determine the defects ofthe pile foundation and provide guarantee for the safety and stability of the superstructure structure.

Key words ：low strain； pile foundation defect；on-site measurement；digital simulation； power response

當前，國內外眾多學者開展了許多關于樁基缺陷檢測的研究，例如，張云鵬修正了Rayleigh-Love桿件理論，采用理論推導的方法得出了低應變動力測樁的三維傳播解析解，認為信號疊加法可以很好的消除高頻橫波的干擾[1]。邸同宇等采用Biot多孔介質連續(xù)方程考慮樁體的橫向變形，得出結論認為管樁泊松比與樁底反射信號幅值成反比，與管樁壁厚成正比[2]。王奎華等采用數(shù)值模擬和模型試驗相結合的技術手段研究了不對稱缺陷樁基的樁頂動力響應規(guī)律，研究發(fā)現(xiàn)，樁頂測點的動力響應曲線呈雙閉環(huán)，最明顯的對稱測點在缺陷截面對稱軸上[3]。孔德勇實際工程為例，研究了聲波檢測法測量樁長的實施過程，并與施工現(xiàn)場實際樁長數(shù)據(jù)及抽芯檢測法樁長檢測數(shù)據(jù)進行了對比研究[4]。李建樹基于巖溶地區(qū)的鉆孔灌注樁施工對反射波檢測法的計算原理進行了相關研究，并結合實際工程探討了該方法在巖溶地區(qū)樁基質量檢測中的應用[5]趙爽等采用模型試驗和數(shù)值模擬相結合的方法研究了高承臺樁不同尺寸缺陷的樁身質點動力響應，研究發(fā)現(xiàn)，低應變檢測方法可用于檢測高承臺樁樁身缺陷，且缺陷位置處截面直徑越小，樁身動力響應中

缺陷處反射越明顯[6]。此外，還有一些學者也對樁基質量檢測展開過相關研究[7-8]；但目前較少有針對缺陷樁基的動力響應展開相關研究。

基于此，依托承德高新區(qū)某改造工程，采用數(shù)值模擬和現(xiàn)場實測相結合的方法，對低應變動力荷載作用下缺陷樁基的動力響應規(guī)律進行研究，為缺陷樁基的識別、判定提供更為確切的依據(jù)，進而為建筑結構的安全性穩(wěn)定性提供保障。……