(Shandong Institute of Geology and Mineral Resources, Jinan 2500 14)
Author: Yu Shilin (1964-), mainly engaged in hydrogeology and engineering geology.
Abstract: With the rapid development of social economy in Jinan, a series of geological problems have emerged. For example, spring water is cut off, groundwater pollution, geological disasters and engineering geological problems. Based on the comprehensive study of hydrogeology, engineering geology, environmental geology and geothermal geological conditions in Jinan, this paper expounds the distribution of engineering geological conditions, unfavorable geological problems and geological disasters in Jinan, and demonstrates the suitability of engineering construction in different sections of Jinan. This paper analyzes and evaluates the present situation of groundwater pollution, groundwater quality and the causes of spring water cut-off, and puts forward some measures for groundwater protection and spring water protection. This paper analyzes the scope of geothermal field and the development prospect of geothermal resources in northern Jinan, and puts forward the feasible scheme of geothermal resources development planning. The construction of underground section of Jinan rail transit and the protection of spring water are analyzed and demonstrated. The feasibility of urban expansion, small watershed management, water environment protection, geological landscape protection, recharge, controlled exploitation of water resources storage conditions and recharge project are analyzed and demonstrated.
Keywords: Jinan; Multi-parameter; Geological environment; Analysis; evaluate
The geological conditions in Jinan area are very complicated. With the rapid development of social economy in Jinan, due to human activities and meteorological factors, a series of environmental geological problems have been triggered. For example, the contradiction between "supply" and "demand" of water resources is prominent, geological disasters and bad engineering geological problems have caused potential hidden dangers to the planning and construction of Jinan New City, Baotu Spring, which has a strong spring source and surging water like a wheel, has been cut off, and the "spring city" exists in name only. Through the comprehensive study of basic geology, hydrogeology, engineering geology, environment and geothermal geological conditions in Jinan, we can master various geological elements and analyze their influence on urban development.
1 safety analysis of spatial geological environment for urban development
1. 1 Analysis of geological environment conditions of engineering construction layer
Jinan area belongs to the engineering geological area of low mountains and hills in central and southern Shandong and the engineering geological area of Yellow River Plain in northwest Shandong, and its plane distribution has obvious east-west zonal distribution characteristics. In the south, Pingyin-Jinan carbonate rock is a stable subregion, which is widely distributed in hard-hard medium-thick layered limestone from Middle Cambrian to Middle Ordovician. The surface karst is developed, and the mechanical strength of rock is high, but the terrain fluctuates greatly and the engineering geological conditions are good. The central part is mainly distributed in the piedmont alluvial and diluvial strata, and the lithology is loess, silty clay, clay, gravel soil and gravel. The engineering geological conditions are good, and there are mainly bad engineering geological problems such as loess collapse. The northern part of the work area is the floodplain of the Yellow River, and the alluvial deposits of the Yellow River are widely distributed. The lithology is silty soil, silty clay, silty fine sand, etc. The upper stratum is loose and unconsolidated, with poor physical and mechanical properties and low bearing capacity. The main adverse engineering geological phenomena are liquefaction of soft soil and sandy soil.
1.2 Adverse engineering geological problems and distribution of geological disasters
1.2. 1 Bad engineering geological problems
The main unfavorable engineering geological problems in the working area are: ① Collapsible loess, which is widely distributed in the southern piedmont and intermountain valleys, with the thickness generally less than 5m, and the collapsibility grade is Grade I micro-unweighted loess collapsibility site; ② Soft soil, mainly distributed near the banks of the Yellow River and Xiaoqing River, and also distributed near Daming Lake, with a thickness generally less than 2m; (3) Liquefied soil, recently accumulated saturated sand and saturated silt are widely distributed in the north of the Yellow River, and there is the possibility of sand liquefaction. The liquefaction grade of foundation is generally mild to moderate.
1.2.2 Types and distribution of geological disasters
There are many kinds of geological disasters in Jinan, especially sudden geological disasters, focusing on geological disasters such as collapse, landslide, debris flow, ground collapse and ground fissures. Collapse, landslide and debris flow are mainly concentrated in southern mountainous areas and piedmont areas, which are mostly caused by human engineering activities. Land subsidence and ground fissures are mainly distributed in the east of Jinan, and scattered in other areas, mostly caused by human mining activities such as coal mines and iron mines and a large number of groundwater exploitation.
1.3 project construction suitability evaluation
The stratum distribution in Jinan area is generally zonal in east-west direction, and its engineering construction suitability is obviously zonal. According to the difficulty of foundation treatment in engineering construction and the economy of engineering construction, it can be divided into four types from the analysis of engineering geological conditions: suitable area, suitable area, poor suitable area and unsuitable area.
1.3. 1 applicable area
The suitable area is mainly distributed in the middle of the working area, which is in the form of east-west belt, and is a stable engineering geological environment area formed by piedmont alluvial plain or intermountain alluvial slope. This area is suitable for building multi-storey buildings and high-rise buildings. Multi-storey buildings can use natural shallow foundation, ordinary small high-rise buildings can use natural raft foundation, and high-rise buildings can use deep foundation pit, raft foundation or box foundation.
1.3.2 Applicable area
It is suitable to be divided into three sections, the southern part is mainly distributed in mountain valleys, which is suitable for building multi-storey buildings and high-rise buildings, but the impact on geological landscape should be considered; The middle part is located in the contact zone between the piedmont alluvial plain and the Yellow River alluvial plain, which is suitable for building multi-storey buildings. The high-rise buildings adopt natural foundation raft foundation and pile foundation. The north is located in the north of the Yellow River, which is suitable for building multi-storey buildings. Raft foundation or composite foundation can be used, and high-rise buildings are not suitable.
1.3.3 Bad suitable area
The poor suitability distinguishes two areas, and the southern area is located in the hilly area with a terrain slope greater than 30; The northern region is located in the soft soil distribution area on both sides of the Yellow River. Pile foundation can be used for multi-storey buildings in this area, which is not suitable for high-rise buildings.
1.3.4 is not suitable for building area.
It is not suitable for scattered construction areas, and the south is located in the area prone to geological disasters, especially in areas where landslides and mudslides do great harm to people's lives and property; Other areas are mined-out subsidence areas, which are very destructive to buildings.
2 Water environmental quality assessment
2. 1 groundwater pollution status
2. 1. 1 groundwater quality change in Jinan area
In recent years, with the intensification of human activities and mining efforts, the quality of karst water in Jinan has gradually deteriorated, especially since the 1980s, the chemical composition of karst water has increased rapidly. In 2004, the salinity of karst groundwater was 1.53 times that of 1.59 years, and the total hardness was 1.22 times, which was 25.34 times. The quality of groundwater in the refinery area is very poor, and oil pollution has been found. The hardness and salinity of some mechanical wells exceed the standard of drinking water. In 2004, the urban salinity was 1.32 1 .958, the total hardness was1.1.04 times, and the Cl- was 4.43 times and/kloc-0 times. In 2004, the salinity of groundwater in the eastern suburbs was 2.09 times that of 1958, and the total hardness was 7.75 times that of 1.46 times.
2. 1.2 Karst water pollution status
Karst water pollution is mainly conventional ion pollution (including total hardness, total dissolved solids, nitrate, nitrite, sulfate, etc. ). The over-standard rates of nitrate and total dissolved solids in Jinan area are 1.6%, 3.2% and 4.8% respectively, and the over-standard rate of total hardness is 12.9%. The hardness, salinity and maximum over-standard multiple are 3.0 times, 2.5 times and 4.8 times respectively, indicating that the groundwater has been polluted by industry. The pollution of five toxic elements (phenol, cyanide, As, Cr6 ++ and Hg) is relatively light, which is only point pollution where industrial and mining enterprises are located. The content of heavy metal ions (copper, lead and zinc) in polluted natural water is low. Oil pollution is mainly distributed near refineries in the eastern and western suburbs.
2.2 Groundwater quality evaluation
According to the comprehensive evaluation of groundwater quality, it can be divided into: ① areas with good water quality. Limestone is widely distributed in the exposed area of low mountains in the southern suburbs to the concealed area in the north. The type of groundwater is mainly HCO _ 3-Ca, and its hardness is generally less than 400mg/L, and its salt content is generally less than 500 mg/L. All hydraulic indexes meet the drinking water quality standards, and the water quality is good, which is suitable for domestic or industrial water supply. ② Areas with good water quality. It is distributed in the periphery of areas with poor water quality and connected with areas with good water quality. The components of groundwater do not exceed the Class III standard of groundwater quality, so it can be used as a centralized water supply source. ③ Areas with poor water quality. Mainly distributed in Houweihua Village, Houlongwo Village, College of Political Science and Law, etc. In addition, there are still some places in the east and west suburbs, such as Immobile, Armed Police Hospital, Sauer and Northern Confucianism. Some projects in groundwater exceed the drinking water quality standard and are suitable for farmland irrigation and industrial water use. It needs to be used as a drinking water source. ④ The water quality is extremely poor. It is only distributed in Jingjiagou village, and the comprehensive evaluation is V-graded water area. Groundwater is mainly polluted by industry and agriculture and is not suitable for drinking.
2.3 Cause analysis of spring water cut-off
With the increasing demand for water resources in urban development, the water level has dropped year after year, and the spring water has been cut off, which not only affects the tourism industry in Jinan, but also affects the water quality of Daming Lake and Xiaoqing River. Reasons for spring water cut-off: ① Artificial exploitation is the main reason for spring water cut-off. Since the end of 1960s, the exploitation of karst groundwater has increased year by year, and it is an indisputable fact that the spring water is cut off due to a large number of groundwater exploitation. In 1950s and 1960s, the amount of groundwater exploitation was only (4.7 ~12.6 )×104m3/d, and the amount of groundwater exploitation in the periphery was relatively small. With the development of the city, the demand for water resources increases year by year, the water level decreases year by year, and the spring flow decreases. The urban spring water has been cut off for the first time since the dry season of 1972, and the total output of water plants and industrial self-provided wells in the eastern suburbs, western suburbs and urban areas has been basically stable at about 55× 104m3/d since the 1990s. (2) With the expansion of the city, the area of the direct recharge area decreases, and the southward expansion of the city reduces the recharge of the spring area. (3) The recharge of indirect recharge area is reduced, and the recharge of surface water of reservoirs in southern mountainous areas is reduced. ④ Climate change and precipitation decrease. ⑤ Influence of indiscriminate mining and excavation on geological environment.
3 geothermal resources development perspective planning
The caprock of geothermal field in the north of the work area is Cenozoic Quaternary and Neogene, Paleozoic Permian and Carboniferous. The thermal reservoir is middle and lower Ordovician limestone; Normal geothermal flow is the main heat source, and the boundary of geothermal field and internal deep faults are the communication channels between underground hot water and deep heat source. The buried depth of the thermal storage roof increased from 200 meters to nearly 3000 meters from south to north.
3. 1 Economical geothermal resource exploitation area
The buried depth of thermal storage in this area is less than 2000 meters, which is convenient for mining and has good economic benefits. According to the difference of buried depth of 500 meters, the area is further divided into four sub-areas: area I is located in the limestone belt in the south of geothermal field and Taoyuan-Dongjia area in the east, with the buried depth of thermal storage roof less than 500 meters, the suitable completion depth less than 700 meters, and the predicted thermal storage temperature of 25 ~ 40℃; Area II is located in the periphery of limestone belt, and it is distributed in a nearly east-west belt. From Shimenzhang-Jiuqu River-Beijiao Forest Farm-Jinjia-Qihe Yawangkou, the buried depth of thermal storage roof is 500 ~1000m, the suitable completion depth is 700 ~1200m, and the predicted thermal storage temperature is 40 ~ 50℃. The third zone is located in the northern part of Balizhuang-Jiaobin-Bai Biao Temple-Sungeng-Qingning-Yao Qiang Airport, and it is distributed in an arc belt. The buried depth of thermal storage roof is 1, 000 ~ 1, 500m, the suitable well completion depth is 1, 200 ~ 1, 700m, and the predicted thermal storage temperature is 50 ~ 60. Area IV is located in Baibiaosi-Sungeng-Huihe area, with buried depth of thermal storage roof1500 ~ 2000m, suitable completion depth1700 ~ 2200m, and estimated thermal storage temperature of 65 ~ 80℃.
3.2 times the exploitation area of economic geothermal resources
This area is located on the south side of Guang Qi fault, and the buried depth of thermal storage is 2000 ~ 3000 m, so the mining technical conditions are difficult and the economic conditions are unreasonable. Due to the large buried depth of thermal storage and high thermal storage temperature, it is estimated that the thermal storage temperature is 80 ~ 90℃ and the completion depth is 2200~3200m.
4 analysis of geological environment protection of urban development space
4. 1 underground section construction of rail transit and spring water protection
4. 1. 1 engineering condition analysis
The underground section of Jinan Rail Transit 1 Line 1 is planned to start from jiefang bridge in the east and Weijiazhuang in the west. Located in the center of the bustling Spring City, it is about 3000m long, with a buried depth of 16m and a tunnel height of 6.4m..* * * The underground section of Qingtuan Road-Qinglong Bridge is about 1700m long, with four springs on both sides.
Quaternary thickness10.7 ~ 210.52 m in the underground section of light rail, the lithology is mainly miscellaneous fill, silty clay mixed with gravel, residual soil, diorite body below, and the buried depth at the bottom is 43.56 ~ 82.49 m, and Ordovician-Cambrian limestone below.
According to the different occurrence media of groundwater, it is mainly divided into loose rock pore water along the line: the water inflow of a single well is less than 500m3/d; Weathering fissure water of intrusive rocks: closely related to pore water of upper loose rocks. The water yield of a single well is less than1000 m3/d, and the water inflow of fractured karst water can reach 5000 ~ 10000 m3/d, and the groundwater level is closely related to precipitation.
Diorite aquiclude is located in the area with thick diorite, and the hydraulic connection between shallow pore fissure water and deep fissure karst water is weak. However, in some areas, such as Wulongtan and Pearl Spring, deep karst water can penetrate diorite, which has a certain hydraulic connection with pore fissure water. The formation of spring water is closely related to topography, strata, geological structure and hydrogeological conditions.
4. 1.2 analysis of the relationship between spring water and pore fissure water
① The recharge sources of karst water and pore water are different, and the runoff and discharge modes are inconsistent; ② The karst water near the spring area is inconsistent with the pore water level; ③ There is a big difference in water abundance between shallow pore fissure water and deep karst water: the single well water inflow of karst water in jiefang bridge-Plymen urban area is above 5000m3/d, and it is between 1000m3/d and 5000m3/d from the north of Pearl Spring and Wulongtan to Daming Lake area, and the single well water inflow of shallow pore fissure water along the line is generally less than 500m3/d, with a large decline. ④ Due to the different hydrochemical characteristics, the karst water quality is good, which meets the drinking water quality standard. Due to man-made pollution, the hydrochemical types of pore fissure water are complex and the salinity is high.
4. 1.3 construction proposal for underground part
The recharge, diameter and discharge conditions of karst spring water and Quaternary pore fissure water are different, and there are differences in water-bearing medium, water abundance, water quality and water level. The main source of spring water supply is the vast southern mountainous area, so such a large spring flow can not come from the Quaternary aquifer. It can be seen that the formation of Jinan spring is extremely complicated, and it is speculated that the spring exposure is related to local structure.
In the area of Hu Ming Road, limestone (marble) is buried deeply. Therefore, regardless of the passenger flow, the underground section of the rail project is suitable for Hu Ming Road.
4.2 Geological environment protection analysis
4.2. 1 Analysis of the relationship between urban expansion and spring protection
4.2. 1. 1 Impact of urban expansion and evolution on recharge
The urban expansion direction of Jinan is mainly east, southeast, south and southwest. Since 1980s, the fastest expansion of urbanization to the south has mainly extended to the southern Ordovician limestone area, where the surface karst is relatively developed, and the leakage recharge area in the direct recharge area is gradually decreasing. Due to the solidification of urban construction ground, surface runoff increases with the increase of years. The urban runoff coefficient was 0.5 in 1960s, and increased to 0.9 in 1990s. As a result, the recharge of underground infiltration is reduced and most of the precipitation is lost. Urban expansion and ground hardening are one of the factors that cause the decrease of spring recharge.
4.2. 1.2 Impact prediction of eastward expansion and westward advancement on groundwater recharge
The downstream of the eastern industrial belt is Baiquan-Wu Jia water source; The east is less than 3 kilometers away from the loess cliff water source. Therefore, the large-scale planning and construction of the eastern industrial belt will inevitably directly affect the allowable exploitation of Baiquan-Wu Jia water source and Huangtuya water source. It is predicted that the construction of the eastern industrial belt will reduce the groundwater recharge by 4.09× 104m3/d in the following year.
(1) West New Town
The Erhuan West Road-Yufuhe area is at the front of the piedmont inclined plain, and the development and construction of this area should be in the northern part of the contact zone between igneous rocks and limestone, namely Duandian-Xihongmiao-dayangzhuang-Danshantun-Xiaojinzhuang; Dangjiazhuang area: located in the upstream of the direct subsidy area, the development should be controlled and the existing sewage discharge points should be effectively treated; Dajiangou-Nankangzhuang line is located in the direct recharge area, which is closely related to urban groundwater. Sewage infiltration will affect the quality of karst water, so this area is not suitable as a planning area.
(2) Changqing University District
The downstream Qiaozili and Lengzhuang water sources are less than 5 kilometers; Stay away from the planned land; It is directly replenished by atmospheric precipitation and flows downstream, which constitutes the important recharge sources of Qiaozili Water Source, Lengzhuang Water Source, dayangzhuang Water Source and Emei Mountain Water Source in Jixi City. Therefore, the planning and construction will have a great impact on groundwater recharge, and it is estimated that the annual infiltration recharge will be reduced by 6.394× 107m3.
(3) Changqing District
Changqing planning area is located in the west of Jinan spring area, Qiaozili and Laozhangzhuang in the northeast of Changqing. There are abundant groundwater resources, and the water inflow of a single well is about 1.04 m3/d, which has the potential of centralized exploitation. The exploitation amount should be controlled below 1× 1.04 m3/d, and the southeast of Changqing is not suitable for large-scale development and construction. Ecological protection should be the leading development direction. Limestone is exposed in a large area in the southern hilly area, which is the direct recharge area of karst water in Jinan spring area. Direct discharge of sewage is prohibited. At the same time, try to reduce the urban planning area in the first-class protection zone, protect the direct recharge area from Ping 'andian to Pancun in the west, from Yufu Valley to Fengqi, and from dayangzhuang-Liu Changshan-Hero Mountain-Yangtouyu-Guodian in the south, and do not reduce the amount of spring water recharge.
4.2. 1.3 Location determination of south control red line
Based on the comprehensive analysis of previous data, in order to avoid the influence of development and construction on spring water supply and promote the sustainable development of Jinan, "South Control" should protect the direct supply area south of the first line of Pingandian-Pancun-Yufu River Basin-Fengqi-dayangzhuang-Liu Changshan-Hero Mountain-Yangtouyu-Niuwang.
4.2.2 Geological environment protection measures
4.2.2. 1 Small watershed control measures
Carry out the principle of "protection in development": take effective measures to prevent siltation and occupation of river valleys, build dams and stop approving development and construction projects in southern mountainous areas. Implement bioengineering, increase afforestation area and protect natural vegetation.
Water Environmental Protection Measures in 4.2.2.2
Limestone is exposed in a large area in the hilly area in the south of Jinan spring area, which is a direct recharge area of karst water. Some gullies are covered by proluvial, but the thickness is small, and the surface karst is developed. The pollutants in this area are easy to infiltrate and pollute groundwater, which belongs to the first-class protection zone. Direct discharge of sewage is strictly prohibited, and urban planning areas in the first-class protected areas are minimized.
Analysis on the Protection of Geological and Geomorphological Landscape in 4.2.2.3
Carbonate strata are widely distributed in Jinan area, and the main minerals are limestone, dolomite, iron ore and granite. Iron ore mining areas are mainly located around the urban area; The exploitation of limestone and dolomite mines is mainly distributed in the vast hilly areas, mainly in the areas near the piedmont. The existing quarrying points or stopping mining points have caused different degrees of damage to landforms and vegetation, affecting the image of the city. The main manifestations are: ① destroying vegetation, aggravating soil erosion and affecting karst water recharge conditions; (2) Destroy the landscape, leaving steep walls, dangerous cliffs and gravel, which is easy to induce geological disasters such as collapse, landslide and debris flow; ③ Impact on water quality.
Feasibility Analysis of Recharge Project in 4.2.2.4
(1) Analysis of replenishment conditions
There is storage space: underground karst is developed in Jinan spring area, with large total displacement, but the annual change of groundwater level is small, so there is storage space for groundwater; Have leakage conditions: the rivers and valleys in the direct recharge area have good leakage conditions, which provide favorable places for recharge; Sufficient water resources: Jinan area has unique advantages, including local surface water resources, Yellow River passenger water resources and Yangtze River passenger water after the implementation of South-to-North Water Transfer Project. Many reservoirs have been built in the southern mountainous area of Jinan Spring Area, with a storage capacity of about * * * 1.8× 108m3. It can be seen that there are a lot of surface water resources in the indirect recharge area that can be used for infiltration recharge. Favorable geological conditions: According to the water discharge and reservoir replenishment test of Wohushan Reservoir in March, 2002 12, it is proved that the Yufu River basin can replenish spring water.
(2) Quantity analysis of supplementary sources
Analysis of Yufu River recharge: the unit length leakage of Zhang Xia limestone in the indirect recharge area is (1.36 ~1.543) ×104m3/(d km). The length of the Yufuhe limestone section south of Pancun is calculated as 10.5km, and the reservoir water supply can be designed according to 65438.
Analysis of North Shahe River recharge: the south of the former Dayan East Bridge is located in the indirect recharge area of the spring area, and the south of Weizhuang is located in the direct recharge area. The section from Qiandayan Bridge to Xihe River in Wei Zhuang is 4.5km long, and the calculated unit leakage is1.4225m3/(d km). The limestone section south of Weizhuang is 6.76km long, and the designed recharge of Beishahe is 9.6165×104m3/d. ..
(3) Water quality demonstration
The source water of the Yellow River is not suitable for direct recharge because of its high sediment concentration, but the physical indexes of the water from Yuqing Lake, Queshan Reservoir and Wohushan Reservoir in the south meet the requirements of recharge water. The hardness is 182.26 ~ 286.4 mg/L, the pH value is 7.4 ~ 8.2, the salinity is lower than the drinking water quality standard, the Mn ion content is less than 0. 1mg/L, the H2SiO2 content is less than 20mg/L, the dissolved iron content is less than 0.5mg/L, and the Na+ content is less than 50 mol/L.
(4) Selection of supplementary source areas
① The source areas of Jiangquan-Zhongjing storage and recharge: Meng Jia-Shiheling, Zhongjing-Underground, Jiangquan-Shi Jing East Road gully, with catchment area of 31.7km2. The recharge in this area plays an important role in the recharge of karst water in the northern high-tech development zone. Reducing the intrusion of spring water supply in the eastern suburbs and improving the deteriorating ecological environment nearby are of great significance for restoring spring water and slowing down the continuous expansion of groundwater drop funnel in the eastern high-tech development zone. ② Xinglong-watershed recharge area: There are six river valleys, namely Xinglong, Xiaolingzi, Peninsula Well, Xiezishan, Huashanyu and Baishiyu, which are located in the upper reaches of and close to the four major spring groups, and this area is directly related to the four major spring groups. Therefore, the recharge of water in this area has a direct recharge effect on spring water. (3) Sauer-Lashan recharge area: distributed in Lashan River. Recharge in this area is conducive to reducing the intrusion of self-provided wells in the western suburbs on spring recharge. ④ Water source of Zhaitou-Luoerbu in Yufu River: This area is a typical area where surface water supplies karst water, which is conducive to reducing the invasion of spring water supply by Xijiao Water Plant. The main recharge river is Yufu River, and there are Wohushan Reservoir and Jinxiu River Reservoir in the upper reaches. ⑤ Beishahe Gushan barrage-Pipashan recharge source area: Yuezhuang Reservoir regularly discharges water, which is of great significance for improving the geological environment of the water source area to be mined. The regulation and storage area of Beishahe River is mainly located between Gushan barrage and Pipa Mountain, with serious surface water leakage. Dongfeng Reservoir is built in the river, which provides favorable conditions for water supply. ⑥ Chua-Ganggou Supplementary Water Source Area in Bai Quan Spring Area: With the planning and construction of the eastern industrial belt, the urban built-up area in Bai Quan Spring Area is increasing year by year, and the number of enterprises and population is increasing, which affects the downstream water supply. Chua's-Ganggou recharge source is located in the upper reaches of the water source, which is of great significance for improving the geological environment in Bai Quan. The recharge source areas are distributed in Juye River, Ganggou River and Zhangjinhe River.
(5) reinjection and reinjection engineering measures
(1) Linear recharge: harness the existing river valley, and make the surface water naturally seep down along the river valley. ② Infiltration of reservoirs and ponds: A certain amount of water has accumulated in reservoirs and ponds, which not only increases the infiltration pressure, but also prolongs the infiltration time. The amount of infiltration is large, and the completed reservoirs can be used after dredging. Dams can be built in areas with favorable water storage to increase the infiltration of surface water. ③ Well-point grouting method: large-diameter seepage wells are laid and directly poured into karst aquifer by using free water head or water pump. It is suggested that Jinxiuchuan Reservoir should release water to supplement the southern part of the city, Wohushan Reservoir should release water along the Yufu River to supplement the western suburbs and the southwestern part of the city, Yuezhuang Reservoir should release water along the Beishahe River to supplement the newly opened water source in the western suburbs, Jiangshuiquan Reservoir should supplement the water source in the eastern suburb development zone, and Langmaoshan Reservoir should supplement the water source in Bai Quan Spring Area. The Yellow River can be used to supplement the water source in continuous drought years.
Analysis on Sustainable Utilization and Spring Protection of Karst Groundwater in 4.2.2.5
In order to maintain the sustainable utilization of karst groundwater resources in Jinan spring area and protect spring water, it is necessary to rationally develop and utilize water resources, implement water supply in different quality, make full use of guest water resources, implement recharge in southern mountainous areas and protect the ecological environment.
(1) Rational exploitation of groundwater as domestic and cutting-edge industrial water.
Under the condition that the water level in Jinan spring area is not less than 27.5 meters in dry season, the recharge in southern mountainous area is 25× 104m3/d, the exploitable karst water in Jinan spring area is 33.5× 104m3/d, and the reuse of spring water is 5× 104m3/d ... East Bai Quan Spring in Jinan spring area. Some boreholes in Xichang-Xiaoxiao water source area in the spring area flow by themselves during the wet season, and the water level changes by 2 ~ 4m. The local industrial and agricultural exploitation is less, and the water source area is still in a natural state. It is suggested to increase the exploitation amount of 8×104m3/d. A total of 69.79× 104m3/d of high-quality groundwater resources can be used for domestic and precision industrial water. If the domestic water consumption is calculated as 120l/ (day, person), the high-quality karst groundwater resources can meet the domestic water consumption of 5.8 million people.
Close the industrial self-provided wells in the periphery of the city and reduce the amount of spring water recharge in the periphery. Agricultural irrigation mainly uses surface water, and the use of karst groundwater is restricted on the premise of saving water. The planning area of "North Span" is a potential area for geothermal resources development, and the recharge condition of underground hot water is poor, so the exploitation amount should be limited, and the Yellow River water of Queshan Reservoir can be used as the water supply source.
(2) Make full use of guest water resources as industrial water sources.
For industrial water with low water quality requirements, surface water resources are given priority. The water supply of Qing Yu Lake and Queshan Reservoir is 80× 104m3/d, the water consumption of medium water conservancy is 23× 104m3/d, and the water consumption of civil air defense trunk roads is 4.0×104m3/d. The total available water supply of surface water and groundwater is After the implementation of the South-to-North Water Transfer Project, the karst groundwater in Baiquan-Wu Jia water source area can be used for drinking water supply. Jinan iron and steel plant, Huangtai power plant, fertilizer plant and heavy machinery plant in the eastern suburbs stopped mining groundwater, and the Yellow River water and Yangtze River water were used as water supply sources. According to the plan, the designed storage capacity of Donghu Reservoir is 5700× 104m3, and the daily water supply is 40×104m3/d.
(3) Comprehensive management and recharge in southern mountainous areas
The surface reservoirs of Wohushan, Jinxiu Chuan and Yuezhuang are used as ecological water to dredge rivers and valleys in southern mountainous areas and build dams. After comprehensive management, water will be drained and replenished from Xinglong-Shilili River, Yufu River and Beisha River. At present, the eastern suburb is short of water, which can be used for the East Lake Reservoir in the east of Longdong in the future. If the high-tech development zone and its southern district replenish water, it will be very beneficial to restore spring water.
5 conclusion
Based on the geological environment conditions related to Jinan's urban construction, this paper discusses it from many aspects, aiming at putting forward some reference suggestions for Jinan's urban construction. However, many problems related to urban construction still need further discussion. It is hoped that relevant departments and industries will make joint efforts to put forward valuable opinions for the urban construction of Jinan.