现代地质
現代地質
현대지질
GEOSCIENCE-JOURNAL OF GRADUATE SCHOOL CHINA UNIVERSITY OF GEOSCIENCES
2015年
2期
434-441
,共8页
姜伏伟%雷明堂%覃有强%戴建玲
薑伏偉%雷明堂%覃有彊%戴建玲
강복위%뢰명당%담유강%대건령
红黏土%渗透变形%抗渗强度%临界条件
紅黏土%滲透變形%抗滲彊度%臨界條件
홍점토%삼투변형%항삼강도%림계조건
clay%seepage failure%anti-permeability strength%critical condition
土的渗透变形是很多地质灾害及岩土工程事故的主要原因之一，但目前黏土的渗透破坏临界条件研究较少。从微观角度分析了黏土在外界驱动水压作用下的渗透破坏过程，以抗渗强度作为黏土渗透破坏临界条件参数。为获取此参数，设计了模拟外界驱动水压作用下，黏土渗透破坏过程的抗渗强度试验装置及方法。选取广西桂林红黏土层底部原状样，测试了32组不同厚度试样，并得出各试样抗渗强度。依据试验结果，分析了抗渗强度受渗透方式和尺寸效应的影响，并采用ArcGis软件统计分析试样抗渗强度的差异性。最终选择15组实际渗透厚度2.5 cm试样的试验结果平均值40.8 kPa，为工程场地黏土抗渗强度值。通过比较抗渗强度值与钻孔实际监测渗透水压，评价工程场地内黏土渗透破坏形成土洞塌陷的可能性。评价结果表明，目前工程场地内黏土渗透驱动水压低于抗渗强度，不具备形成土洞的条件。经实地勘察，评价结果符合现场实际情况。
土的滲透變形是很多地質災害及巖土工程事故的主要原因之一，但目前黏土的滲透破壞臨界條件研究較少。從微觀角度分析瞭黏土在外界驅動水壓作用下的滲透破壞過程，以抗滲彊度作為黏土滲透破壞臨界條件參數。為穫取此參數，設計瞭模擬外界驅動水壓作用下，黏土滲透破壞過程的抗滲彊度試驗裝置及方法。選取廣西桂林紅黏土層底部原狀樣，測試瞭32組不同厚度試樣，併得齣各試樣抗滲彊度。依據試驗結果，分析瞭抗滲彊度受滲透方式和呎吋效應的影響，併採用ArcGis軟件統計分析試樣抗滲彊度的差異性。最終選擇15組實際滲透厚度2.5 cm試樣的試驗結果平均值40.8 kPa，為工程場地黏土抗滲彊度值。通過比較抗滲彊度值與鑽孔實際鑑測滲透水壓，評價工程場地內黏土滲透破壞形成土洞塌陷的可能性。評價結果錶明，目前工程場地內黏土滲透驅動水壓低于抗滲彊度，不具備形成土洞的條件。經實地勘察，評價結果符閤現場實際情況。
토적삼투변형시흔다지질재해급암토공정사고적주요원인지일，단목전점토적삼투파배림계조건연구교소。종미관각도분석료점토재외계구동수압작용하적삼투파배과정，이항삼강도작위점토삼투파배림계조건삼수。위획취차삼수，설계료모의외계구동수압작용하，점토삼투파배과정적항삼강도시험장치급방법。선취엄서계림홍점토층저부원상양，측시료32조불동후도시양，병득출각시양항삼강도。의거시험결과，분석료항삼강도수삼투방식화척촌효응적영향，병채용ArcGis연건통계분석시양항삼강도적차이성。최종선택15조실제삼투후도2.5 cm시양적시험결과평균치40.8 kPa，위공정장지점토항삼강도치。통과비교항삼강도치여찬공실제감측삼투수압，평개공정장지내점토삼투파배형성토동탑함적가능성。평개결과표명，목전공정장지내점토삼투구동수압저우항삼강도，불구비형성토동적조건。경실지감찰，평개결과부합현장실제정황。
A lot of geological hazards and geotechnical engineering failure cases including slope,dam,construct foundation,et al,are caused by soil seepage deformation.However,it is seldom to study the critical condition of clay seepage failure.This paper represents the microprocess of clay failure caused by additional driving pres-sure,and takes the anti-permeability strength as the critical condition for judging clay seepage failure.Firstly, the equipment and method which stimulate the process of clay failure were designed to test the strength.Second-ly,32 undisturbed samples of clay were tested with different thickness,which are from the engineering field of Tieshan industrial park in Guilin,China.With the testing values of 32 samples,it is concluded that the two factors of seepage ways and sample size influence the anti-permeability strength,and the test results are made by statistical analysis of ArcGis.The average value of 15 samples of 2.5 cm thicknesses,40.8 kPa,is the anti-permeability strength of the engineering field.Finally,by comparing the strength with the seepage water pres-sure in field,the probability of clay seepage failure to form soil-cave collapse is assessed.Results indicate that there is a low susceptibility to the formation of subsidence sinkholes under current conditions,as the seepage water pressure is less than the anti-permeability strength in field.By the field investigation,the assessment re-sult is consistent with the truth.
