长江三角洲浅层气地质赋存特征及其对越江隧道工程的影响  

Geological occurrence characteristics of shallow gas in Yangtze River Delta and their effect on cross-river tunnel

作　　者：郭鹏鹏 王勇[2] 宋湦 陈成[2] 贾鹏飞[4] GUO Pengpeng;WANG Yong;SONG Sheng;CHEN Cheng;JIA Pengfei(College of Civil Engineering and Architecture,Guilin University of Technology,Guilin,Guangxi 541004,China;State Key Laboratory of Geomechanics and Geotechnical Engineering(Institute of Rock and Soil Mechanics,Chinese Academy of Science),Wuhan 430071,China;Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou 310012,China;State Key Laboratory of Continental Dynamics(Northwest University),Xi’an 710069,China)

机构地区：[1]桂林理工大学土木与建筑工程学院,广西桂林541004 [2]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,武汉430071 [3]自然资源部第二海洋研究所,杭州310012 [4]西北大学地质学系大陆动力学国家重点实验室,西安710069

出　　处：《中国科技论文》2024年第1期14-22,共9页China Sciencepaper

基　　金：国家自然科学基金资助项目(51979269,52127815);武汉市应用基础前沿项目(2020010601012181)。

摘　　要：为研究我国长江中下游沿江、沿海平原赋存的浅层气不良地质及其对工程的影响,以长江崇太隧道遭遇浅层气地质为工程背景,基于长江三角洲地理地貌、沉积历史和沉积相特征,通过专项地质勘察和地球化学分析,研究区域浅层气地质的赋存特征,分析其对工程的不利影响,并提出针对性防治措施。结果表明:长江三角洲区域地层互相叠置、层序完整明显,浅海相淤泥质黏土层既是浅层气的产气层,又是封盖层,下覆厚状砂层是气体的良好储集体。隧址区具备典型的长江三角洲沉积特征,地层中赋存的浅层气属于原生甲烷型生物成因气;喷发性气体赋存于浅海相淤泥质黏土层内部的粉土、粉砂微、薄夹层中,属于未经长距离运移的自生、自储、自盖型生物成因气;隧道越江段主要穿越的厚层河口湾相细、中砂层虽具备良好的储气条件,但未见大量气体储集。从越江隧道段浅层气的赋存特征出发,虽然分析认为其对工程的影响程度有限,但在工程建设中仍不容忽视,需采取针对性预防措施以避免浅层气地质造成工程危害。To study the unfavorable geology of the occurrence of shallow gases and their effects on the tunnel engineering in the plain areas along the middle and lower reaches of the Yangtze River,the geological occurrence characteristics of shallow gas in the region were studied by means of special geological survey and geochemical analysis.In the study,the shallow gas geology occurred in the Chongtai tunnel of Yangtze River was taken as an engineering background and the analysis was carried out based on the geographi-cal,sedimentary history,sedimentary facies characteristics of the Yangtze River Delta.The adverse effects of the geological occur-rence characteristics of shallow gas on engineering were pointed out,and targeted prevention and control measures were proposed.The results show that the regional strata are overlap with each other,and the sequence is complete and obvious in the Yangtze River Delta.The silty clay of shallow marine facies are both gas-producing and capping layers,and the thick sand layer covered below is a good reservoir of gas.In the tunnel site,there are typical sedimentary characteristics of the Yangtze River Delta,and the shallow gas in the stratum belongs to the primary methane biogenic gas.The eruptive gas store in the silt soil and silty sand micro-thin interlayers inside the muddy clay layer of shallow marine facies,and it belongs to the self-generating,self-reservoir and self-sealing biogas with-out long distance migration.However,the cross-river section of the tunnel in the primarily passes through thick,fine and medium sand layers of estuarine facies have good gas storage condition,but there is no evidence of large gas accumulation.Based on the occurrence characteristics of shallow gas in cross-river tunnel section,the impact of this occurrence feature of the shallow gas on tun-nel engineering is limited,but it still cannot be ignored in the engineering construction,and targeted prevention measures should be taken to avoid the hazard caused by shallow gas geology.

关 键 词：长江三角洲 浅层气 地质赋存 不良地质 越江隧道 

分 类 号：P694[天文地球—地质学]