工程地质学报
工程地質學報
공정지질학보
2013年
6期
828-834
,共7页
黄勇%周志芳%傅胜%胡大可%李尚高
黃勇%週誌芳%傅勝%鬍大可%李尚高
황용%주지방%부성%호대가%리상고
高压压水试验%岩体透水率%高压单位吸水量%试段压入量
高壓壓水試驗%巖體透水率%高壓單位吸水量%試段壓入量
고압압수시험%암체투수솔%고압단위흡수량%시단압입량
High pressure permeability test%Permeability of rock mass%Specific water absorption of high pres-sure%Injection flux of test section
在水利水电等地下工程的常规压水试验中,一般以1Lu(吕荣值)作为防渗灌浆结束的标准。近年来,随着科学技术水平的不断提高,我国的高水头抽水蓄能电站得到了迅速发展,也进行了相应的高压压水试验。对于高水头的水电工程,现场高压压水试验结果和常规压水试验结果对比发现,对于同一试验段,高压压水试验计算的岩体透水率反而比常规压水试验计算的透水率小,由此计算的岩体渗透系数也偏小,但在高压水作用下岩体渗透性会不同程度地增加。如果岩体透水率还用《水利水电工程钻孔压水试验规程》(SL31-2003)中的公式计算,则由于压力的增加计算的Lu变小,防渗的标准会相应提高。针对规范中岩体透水率的适用性问题,提出了基于高压压水试验的“高压单位吸水量”的概念,即在直径75mm、试段长度约5m的孔内高压压水试验中,围岩在设计水头(≥2MPa)作用下,单位长度上的压入流量,用DK表示,单位为L·min-1·m-1。基于这一概念,应用数值模型计算了岩体试段的压入量,通过与某抽水蓄能电站高压压水试验的实际岩体试段的压入量进行的对比,获得了最大压力为4MPa时,岩体注浆结束标准为2DK(0.5Lu)。因此,对于不同的高水头水电工程,隧洞注浆结束标准(高压单位吸水量)要根据设计水头进行调整,而不能以常水头那样始终以1 Lu作为防渗结束标准。
在水利水電等地下工程的常規壓水試驗中,一般以1Lu(呂榮值)作為防滲灌漿結束的標準。近年來,隨著科學技術水平的不斷提高,我國的高水頭抽水蓄能電站得到瞭迅速髮展,也進行瞭相應的高壓壓水試驗。對于高水頭的水電工程,現場高壓壓水試驗結果和常規壓水試驗結果對比髮現,對于同一試驗段,高壓壓水試驗計算的巖體透水率反而比常規壓水試驗計算的透水率小,由此計算的巖體滲透繫數也偏小,但在高壓水作用下巖體滲透性會不同程度地增加。如果巖體透水率還用《水利水電工程鑽孔壓水試驗規程》(SL31-2003)中的公式計算,則由于壓力的增加計算的Lu變小,防滲的標準會相應提高。針對規範中巖體透水率的適用性問題,提齣瞭基于高壓壓水試驗的“高壓單位吸水量”的概唸,即在直徑75mm、試段長度約5m的孔內高壓壓水試驗中,圍巖在設計水頭(≥2MPa)作用下,單位長度上的壓入流量,用DK錶示,單位為L·min-1·m-1。基于這一概唸,應用數值模型計算瞭巖體試段的壓入量,通過與某抽水蓄能電站高壓壓水試驗的實際巖體試段的壓入量進行的對比,穫得瞭最大壓力為4MPa時,巖體註漿結束標準為2DK(0.5Lu)。因此,對于不同的高水頭水電工程,隧洞註漿結束標準(高壓單位吸水量)要根據設計水頭進行調整,而不能以常水頭那樣始終以1 Lu作為防滲結束標準。
재수이수전등지하공정적상규압수시험중,일반이1Lu(려영치)작위방삼관장결속적표준。근년래,수착과학기술수평적불단제고,아국적고수두추수축능전참득도료신속발전,야진행료상응적고압압수시험。대우고수두적수전공정,현장고압압수시험결과화상규압수시험결과대비발현,대우동일시험단,고압압수시험계산적암체투수솔반이비상규압수시험계산적투수솔소,유차계산적암체삼투계수야편소,단재고압수작용하암체삼투성회불동정도지증가。여과암체투수솔환용《수이수전공정찬공압수시험규정》(SL31-2003)중적공식계산,칙유우압력적증가계산적Lu변소,방삼적표준회상응제고。침대규범중암체투수솔적괄용성문제,제출료기우고압압수시험적“고압단위흡수량”적개념,즉재직경75mm、시단장도약5m적공내고압압수시험중,위암재설계수두(≥2MPa)작용하,단위장도상적압입류량,용DK표시,단위위L·min-1·m-1。기우저일개념,응용수치모형계산료암체시단적압입량,통과여모추수축능전참고압압수시험적실제암체시단적압입량진행적대비,획득료최대압력위4MPa시,암체주장결속표준위2DK(0.5Lu)。인차,대우불동적고수두수전공정,수동주장결속표준(고압단위흡수량)요근거설계수두진행조정,이불능이상수두나양시종이1 Lu작위방삼결속표준。
Usually,1 Lu is considered to be the standard of terminating anti-seepage grouting in conventional pres-sure permeability test for the engineering of water conservancy and hydropower.With the development of science and technology,many pumped storage power stations have been or will be constructed.Test data show that permea-bility of rock mass is smaller using the high pressure test than that of conventional pressure permeability test.But for hydropower project with high hydraulic head,if permeability of rock mass is still calculated using《Water Resources and Hydropower Engineering Borehole Water Pressure Test Procedures》(SL31-2003),the standard of anti-seepage grouting can be improved due to the decrease of Lu values with the increase of water pressure.For the applicability of the formula under the condition of high hydraulic head,specific water absorption of high pressure is put forward. It is defined as the injection flux of unit length with the diameter of 75mm,test section length of 5m and designed hydraulic head.It is expressed as DK with the dimension of L·min-1·m-1 .Also,according to the numerical model, the injection flux of test sections for rocks is calculated.The comparison of calculated and measured injection flux is conducted in a pumped storage power station.The results show that when the high water pressure(designed hydrau-lic head)is 4MPa,the accepted standard of terminating anti-seepage grouting is 2DK which is correspondence to 0.5Lu.Therefore,for different hydropower projects,the standard of anti-seepage grouting needs to be changed ac-cording to the designed hydraulic head,instead of 1 Lu.