【作者】 宋凯；

【导师】 李晓；

【作者基本信息】 成都理工大学 ， 环境工程， 2011， 硕士

【摘要】 本文以西藏自治区桑日县沃卡盆地温泉为研究对象,在分析区域地热地质背景的基础上,结合研究区温泉出露特征,水化学及同位素特征,对沃卡温泉的受控因素和形成条件进行了分析研究。温泉的出露呈北东向带状展布,与沃卡盆地西边界断裂的方向相似,区内温泉的分布与断裂构造的关系密切。根据水化学特征与氢氧稳定同位素地球化学特征分析表明,研究区温泉的主要阳离子成分为Na+,阴离子主要成份为SO42-,Cl-的含量与温泉温度有紧密的相关性,热水微量元素含量与西藏热水总体背景值相近,且明显高于地表水。根据与西南大气降水线对比,温泉水主要来源与大气降水补给,利用同位素特征推算补给区年平均温度为-9℃,补给高程在5000～5300m之间。利用多种地球化学温标及混合模型计算法估算出沃卡温泉热储温度介于77～133℃之间。本文通过对研究区地热形成条件及地热梯度的计算,温泉增温与区域内传导热流所能提供热量基本相当,说明沃卡温泉热量主要来源与深循环中吸收围岩热量,并无特殊的外加热源,热储类型主要为断裂带型即温泉主要储存于断裂破碎带中,区内温泉类型主要为断裂深循环型。通过对沃卡温泉形成条件分析,温泉的水源主要来源于增久曲与墨竹曲分水岭地带,大气降水在补给区,沿基岩裂隙网络下渗,汇集于沃卡盆地西缘边界断裂中进行深部循环,地下水在漫长的循环过程中充分吸收了岩石深处的热能形成地下热水,然后在沃卡韧性剪切带等阻水断层相交部位的构造破碎带上升,最后在地质构造的有利部位上涌出露。结合前述分析资料,为对隧道施工各段位岩温进行较为准确预测,建立温泉多种循环模式并结合区域大地热流值对沃卡地区的地温梯度估算,并对拉隆隧道各段岩温进行预测,地热对隧道可能会产生一定影响,估测结果显示无中等危险区,仅在埋深较大及穿越沃卡盆地区域评级为微危险区,占隧道全长的49%,仅需做加强通风进行处理。研究区地热发育具有明显规律,地热异常带发育明显受断层控制,根据沃卡温泉的形成特征,由于东西向阻水断层的阻隔,隧址区地下水系统由于水力条件限制,地下水循环深度无法供应充足热量形成高热流体,即隧道开挖过程中遇到高热地热流体的可能性不大。沃卡温泉地下水系统与拉隆隧道穿越区地下水系统联系不紧密,拉隆隧道的开挖而引起对沃卡温泉的袭夺的可能性不大。因此,以现拟选线路方案穿越沃卡盆地,虽会对地下水系统有一定影响,但是产生较大范围的地下水疏干及对沃卡温泉泉群的袭夺的可能性不大。穿越沃卡盆地的方案是较为可行的。更多还原

【Abstract】 This paper chooses the voca hot-springs in Tibet autonomous region as research object.Though analyzing the region geothermal and geologic background, do some researchs on the hot-springs distribution characteristics and its control factors,that find the springs appear on the zonal distribution along the esat-south,the direction as same as the west-border of voca basin,which show the distribution of springs has intimate connection with the fractures.Across the study of hydrochemical and isotope geochemical characteristics, Hot Springs is the main cation Na+, the main ingredients of anions SO42-, and the content of Cl- and hot temperatures are closely correlated. Hot-springs trace elements are close to background values in Tibet, and it significantly higher than surface water. With the comparison to Southwest meteoric water line, the main source of hot spring water from rainfall.the projected average annual temperature of recharge area -9℃, and supplies region between 5000 ~ 5300m elevation. Geochemical temperature scale and mixed use model calculations to estimate the storage temperature range of hot Voca 77 ~ 133℃between.Based on the geothermal gradient of the formation conditions and the calculation of geothermal, hot spring temperature and heat flow within the region can provide the heat conduction is roughly equal, it is mean that the main heat source of hot springs absorbing surrounding heat though deep-cycle, no special additional heat.The heat storage is fault type that is mainly stored in the hot spring fractured zone, and the area consists mainly of spring break deep cycle type. The forming conditions by analysis of hot spring water,comes mainly from Zengjiu river and bamboo river by watershed area, precipitation in the recharge area, infiltration along the bedrock fracture network, bringing together the western margin of the basin boundary fault Voca conducted deep circulation of groundwater circulation in the long process of fully absorb the heat of the rock formation deep underground hot water, then water blocking Voca ductile shear zone and other parts of the structural fault fracture zone intersected up, the last part in the favorable geological structure exposed on the emission. Integration of the aforementioned analysis of data for the construction of the tunnel for the more accurately predict the rock temperature.geothermal gradient was estimated though circulation patterns of Hot Springs with the regional heat flow value on the Voca area. La Long tunnel sections to predict rock temperatures.There are no medium-risk areas ,and only in the depth of the area and across the Voca area rated as slightly dangerous, accounting for 49% of total length of the tunnel, only to do processing to enhance ventilation.geothermal and the tunnel may have an impact. Geothermal development in the study area has a significant distribution, with the development of geothermal anomaly was controlled by faults, the formation of features according to Voca springs, water was blocked by east-west faults of the barrier. Voca hot water systems and the tunnel through the area belong to different hydrogeological units.With the limite of hydraulic conditions, water can not absorb a lot of heat for deep cycle and the formation of high heat flow, the heat encountered during tunnel excavation geothermal fluid is unlikely . Voca hot water systems and groundwater systems Lalong tunnel was through contact does not close.Lalong tunnel excavation of the tunnel caused the capture of Voca Spa is unlikely. Therefore, it is proposed to select the program through the Voca basin, groundwater system though will have some influence, but have a greater range of groundwater dewatering and hot spring on the Voca Capture group is unlikely.The program through the Voca basin is more feasible.更多还原