工程地质学报
工程地質學報
공정지질학보
2015年
3期
554-563
,共10页
刘子金%袁代江%武兴亮%张磊
劉子金%袁代江%武興亮%張磊
류자금%원대강%무흥량%장뢰
平寨水库%溶洞%发育特征%灌浆廊道%形成机制
平寨水庫%溶洞%髮育特徵%灌漿廊道%形成機製
평채수고%용동%발육특정%관장랑도%형성궤제
Pingzhai reservoir%Karst cave%Development characteristics%Grouting tunnel%Formation mechanism
平寨水库坝址区以碳酸盐岩为主，岩溶较发育，水库左岸底层灌浆廊道大型充填溶洞，是水库地下工程施工开挖中揭露的规模最大、对水库渗漏影响最大、设计及施工处理难度最大的溶洞。本文以工程前期地质勘察工作为基础，在区域地貌、地质构造格局、地层岩性、地表及地下水系发育特征研究的基础上，结合工程防渗施工揭露的岩溶水文地质现象、洞穴充填物研究等，从可溶性岩层、地下水来源及运移途径、暗河冲刷与洞顶坍塌作用4个方面，对溶洞发育形成机制进行了研究。分析认为，鸡场背斜北西翼纵向张裂隙和横张裂隙及层间滑脱、断裂破碎带，为五里大洞—鸡场洼地—上坝洼地地下水向三岔河的径流提供了运移的原始空间与通道，形成溶洞的地下水为五里大洞—鸡场洼地—上坝洼地地下暗河，长期溶蚀作用使裂隙通道变为溶蚀宽缝并最终转化为岩溶管道，岩溶水沿此通道在左岸底层灌浆廊道桩号0＋238～0＋296m 附近下中部岩体呈虹吸状循环，地下水的强烈冲刷与洞顶坍塌在溶洞形成过程中的作用巨大，后因深部径流条件改变，岩溶管道被逐渐堵塞，形成如今的大型充填溶洞。
平寨水庫壩阯區以碳痠鹽巖為主，巖溶較髮育，水庫左岸底層灌漿廊道大型充填溶洞，是水庫地下工程施工開挖中揭露的規模最大、對水庫滲漏影響最大、設計及施工處理難度最大的溶洞。本文以工程前期地質勘察工作為基礎，在區域地貌、地質構造格跼、地層巖性、地錶及地下水繫髮育特徵研究的基礎上，結閤工程防滲施工揭露的巖溶水文地質現象、洞穴充填物研究等，從可溶性巖層、地下水來源及運移途徑、暗河遲刷與洞頂坍塌作用4箇方麵，對溶洞髮育形成機製進行瞭研究。分析認為，鷄場揹斜北西翼縱嚮張裂隙和橫張裂隙及層間滑脫、斷裂破碎帶，為五裏大洞—鷄場窪地—上壩窪地地下水嚮三岔河的徑流提供瞭運移的原始空間與通道，形成溶洞的地下水為五裏大洞—鷄場窪地—上壩窪地地下暗河，長期溶蝕作用使裂隙通道變為溶蝕寬縫併最終轉化為巖溶管道，巖溶水沿此通道在左岸底層灌漿廊道樁號0＋238～0＋296m 附近下中部巖體呈虹吸狀循環，地下水的彊烈遲刷與洞頂坍塌在溶洞形成過程中的作用巨大，後因深部徑流條件改變，巖溶管道被逐漸堵塞，形成如今的大型充填溶洞。
평채수고패지구이탄산염암위주，암용교발육，수고좌안저층관장랑도대형충전용동，시수고지하공정시공개알중게로적규모최대、대수고삼루영향최대、설계급시공처리난도최대적용동。본문이공정전기지질감찰공작위기출，재구역지모、지질구조격국、지층암성、지표급지하수계발육특정연구적기출상，결합공정방삼시공게로적암용수문지질현상、동혈충전물연구등，종가용성암층、지하수래원급운이도경、암하충쇄여동정담탑작용4개방면，대용동발육형성궤제진행료연구。분석인위，계장배사북서익종향장렬극화횡장렬극급층간활탈、단렬파쇄대，위오리대동—계장와지—상패와지지하수향삼차하적경류제공료운이적원시공간여통도，형성용동적지하수위오리대동—계장와지—상패와지지하암하，장기용식작용사렬극통도변위용식관봉병최종전화위암용관도，암용수연차통도재좌안저층관장랑도장호0＋238～0＋296m 부근하중부암체정홍흡상순배，지하수적강렬충쇄여동정담탑재용동형성과정중적작용거대，후인심부경류조건개변，암용관도피축점도새，형성여금적대형충전용동。
The dam area of Pingzhai reservoir is dominated with carbonate rocks.Karst develops seriously.A large filled karst cave is discovered in bottom grouting gallery on the left bank of dam site.It is the largest in scale and it mostly affects the seepage of reservoir.The design and construction about the cave are the most difficult one among all of the caves discovered during the excavation of underground engineering.This paper is based on the engineering geological exploration carried on before design stage and the study about regional landforms,geological structure, stratum lithology and river system of surface and underground water.It further combines the karst hydro geological phenomenon and cave fillings discovered during the construction of curtain grouting engineering.This paper examines the four aspects including soluble rock,groundwater sources and transport and erosion of underground river,collapse of cave roof.It studies the formation mechanism of karst development,carries on the analysis.It finds that there are the NW longitudinal tension fractures and horizontal tensile cracks on Jichang anticline and interlayer gliding,and the fault structural fracture zone.They provide the original space and channel for karst system of Wuli Cave-Jichang depression-Shangba depression runoff to Shanchahe.They provide the formation of karst caves of groundwater,the long-term corrosion caused fissure channel to wide crack then to karst pipe,and forms the inverted siphon circulation of karst water at 0+220m—0+238m of mileage in the bottom grouting gallery on the left bank.Strong erosion and roof collapse are also immensely helpful in cave formation.Due to deep runoff conditions are changed and channel for karst gradually is filled,the large filled karst cave is developed finally.
