岩土力学
巖土力學
암토역학
ROCK AND SOIL MECHANICS
2014年
7期
2029-2040
,共12页
黄土高边坡%土钉-预加固桩%性状%动态监测%有限元%稳定性分析
黃土高邊坡%土釘-預加固樁%性狀%動態鑑測%有限元%穩定性分析
황토고변파%토정-예가고장%성상%동태감측%유한원%은정성분석
high loess slope%combination of soil nails and stabilization piles (CSNSP)%behavior%dynamic monitoring%finite elements%stability analysis
土钉-预加固桩复合支护技术已在基坑及边坡工程中取得了大量应用,但在黄土高边坡开挖中的应用相对较少。基于详细的现场监测数据并辅以有限元数值计算,分析了边坡开挖过程中支护体系受力及变形随时间和空间的变化规律。结果表明:预加固桩的水平位移随着时间的推移与开挖深度的增加呈增大趋势,并最终趋于稳定,同时,桩身剪力及弯矩亦随开挖的进行而不断增大;剪力最大值的位置不断下移,说明边坡的潜在滑动面有不断向下扩展的趋势。与深基坑支护桩的土压力分布相比,土钉-预加固桩复合支护体系中桩后土压力随开挖呈不断减小的趋势,但桩前土压力随着开挖深度的增加,有增有减。随着施工开挖深度的增加,土钉所测得的应力有着明显的增大,说明土钉对抑制坡体变形起到了一定作用。在预加固桩的影响下,桩上方坡体的最危险破裂面为圆弧状,其剪出口位于预加固桩桩顶处。开挖深度较浅时,土钉对整体稳定性的贡献较大,而随着开挖深度的变大,预加固桩的加固效果开始占主导地位。
土釘-預加固樁複閤支護技術已在基坑及邊坡工程中取得瞭大量應用,但在黃土高邊坡開挖中的應用相對較少。基于詳細的現場鑑測數據併輔以有限元數值計算,分析瞭邊坡開挖過程中支護體繫受力及變形隨時間和空間的變化規律。結果錶明:預加固樁的水平位移隨著時間的推移與開挖深度的增加呈增大趨勢,併最終趨于穩定,同時,樁身剪力及彎矩亦隨開挖的進行而不斷增大;剪力最大值的位置不斷下移,說明邊坡的潛在滑動麵有不斷嚮下擴展的趨勢。與深基坑支護樁的土壓力分佈相比,土釘-預加固樁複閤支護體繫中樁後土壓力隨開挖呈不斷減小的趨勢,但樁前土壓力隨著開挖深度的增加,有增有減。隨著施工開挖深度的增加,土釘所測得的應力有著明顯的增大,說明土釘對抑製坡體變形起到瞭一定作用。在預加固樁的影響下,樁上方坡體的最危險破裂麵為圓弧狀,其剪齣口位于預加固樁樁頂處。開挖深度較淺時,土釘對整體穩定性的貢獻較大,而隨著開挖深度的變大,預加固樁的加固效果開始佔主導地位。
토정-예가고장복합지호기술이재기갱급변파공정중취득료대량응용,단재황토고변파개알중적응용상대교소。기우상세적현장감측수거병보이유한원수치계산,분석료변파개알과정중지호체계수력급변형수시간화공간적변화규률。결과표명:예가고장적수평위이수착시간적추이여개알심도적증가정증대추세,병최종추우은정,동시,장신전력급만구역수개알적진행이불단증대;전력최대치적위치불단하이,설명변파적잠재활동면유불단향하확전적추세。여심기갱지호장적토압력분포상비,토정-예가고장복합지호체계중장후토압력수개알정불단감소적추세,단장전토압력수착개알심도적증가,유증유감。수착시공개알심도적증가,토정소측득적응력유착명현적증대,설명토정대억제파체변형기도료일정작용。재예가고장적영향하,장상방파체적최위험파렬면위원호상,기전출구위우예가고장장정처。개알심도교천시,토정대정체은정성적공헌교대,이수착개알심도적변대,예가고장적가고효과개시점주도지위。
The combination of soil nails and stabilization piles (CSNSP) has been widely used as a reinforcing technique to retain excavations and stabilize slopes, but few relevant applications are found for high loess slope. Based on a high steep loess slope strengthened by CSNSP, the behavior of the strengthening system is investigated by field monitoring and finite element method. The results show that the lateral displacement, shear force and bending moment of piles increase gradually with the increment of excavation depth;and the displacement tends to be steady gradually. The location of the maximum shear force in the pile body shows a declining trend which indicates that the potential failure surface develops downwards. The distribution of soil pressure around piles in CSNSP system is compared with which appeared in deep foundation pit. The soil pressure on the back side of piles shows a trend of decrease with excavation while the soil pressure on the front side appears to be fluctuant. With the growth of excavation depth, the measured stress of the reinforced soil nails increases significantly, which indicates that the slope deformation is limited by the soil nails. The most dangerous rupture surface of the slope above piles appears to be a circular arc and the shear opening locates at the head of the piles. In addition, the proportion of soil nails to stability for the overall system is larger than the stabilization piles when the excavation depth is shallow, but the situation changes with the increment of the excavation depth.