Yu Shilin, Hu Kezhen, Peng Yuming
(Shandong Provincial Geological and Mineral Engineering Survey Institute, Jinan 250014)
About the author: Yu Shilin (1964—), mainly Engaged in hydrogeology and engineering geology.
Abstract: With the rapid social and economic development of Jinan City, a series of geological problems have arisen. Such as spring water outage, groundwater pollution, geological disasters and engineering geological problems, etc. Through comprehensive research on hydrogeology, engineering geology, environmental geology, and geothermal geological conditions in Jinan, this article clarifies the distribution of engineering geology conditions, adverse geological problems, and geological disasters in Jinan, and demonstrates the suitability of engineering construction in different sections of Jinan. ; Analyzed and evaluated the current situation of groundwater pollution, groundwater quality, and reasons for spring water outage, and proposed measures for groundwater protection and spring preservation; analyzed the scope of geothermal fields and geothermal resource development prospects in northern Jinan, and proposed the feasibility of geothermal resource development planning planning; analysis and demonstration of the construction of the underground section of Jinan Rail Transit and spring water protection; analysis and demonstration of urban expansion, small watershed management, water environment protection, geological and landform landscape protection, recharge and controlled exploitation of water resources regulation and storage conditions and source replenishment projects The feasibility was analyzed and demonstrated.
Keywords: Jinan; multi-parameters; geological environment; analysis; evaluation
The geological conditions in Jinan are very complex. With the rapid development of Jinan’s social economy, the geological conditions are affected by human activities and meteorological factors. The influence of factors has resulted in a series of environmental geological problems. For example, the contradiction between "supply" and "demand" of water resources is prominent, geological disasters and poor engineering geology problems have caused potential hidden dangers to the planning and construction of Jinan New City. The Baotu Spring, "the spring is rising from the source, and the water is gushing like a wheel", has stopped flowing, and the "Spring City" The name no longer lives up to its name. Through comprehensive research on basic geology, hydrogeology, engineering geology, environment, and geothermal geological conditions in urban areas of Jinan City, we can master various geological elements and analyze and study their impact on urban development.
1 Analysis of geological environmental safety of urban development space
1.1 Analysis of geological environmental conditions of engineering construction layer
Jinan area belongs to the engineering geology of low mountains and hills in central and southern Shandong The area and the engineering geological area of ??the Yellow River Flood Plain in northwest Shandong have obvious east-west zonal distribution characteristics. The southern part is the Pingyin-Jinan carbonate rock stable sub-zone, where hard to relatively hard medium-thick layered limestone from the Middle Cambrian to the Middle Ordovician is widely distributed. The surface karst is relatively developed and the rock mechanical strength is high, but the terrain is undulating. , the engineering geological conditions are good; the central part is mainly distributed in piedmont alluvial strata, and the lithology is loess, silty clay, clay, gravel soil, pebbles, etc. The engineering geological conditions are good, but there are mainly unfavorable engineering projects such as loess subsidence. Geological issues: The northern part of the work area is the Yellow River plain, where alluvial deposits from the Yellow River are widely distributed. The lithology is silt, silty clay and silty sand. The upper strata are loose and under-consolidated, with poor physical and mechanical properties and low bearing capacity. The main The undesirable engineering geological phenomena that exist are: liquefaction of soft soil and sand.
1.2 Poor engineering geological problems and distribution of geological disasters
1.2.1 Poor engineering geological problems
The main bad engineering geological problems in the work area are: ① Wet Collapsible loess is widely distributed in the southern piedmont areas and intermountain valleys. The thickness is generally less than 5m. The collapsibility grade is Level I slight non-self-weight loess collapsible site; ② soft soil, mainly distributed near both sides of the Yellow River and Xiaoqing River. In addition, it is also distributed near Daming Lake, and the thickness is generally less than 2m; ③ Liquefied soil, newly accumulated saturated sand and saturated silt are widely distributed north of the Yellow River. There is the possibility of sand liquefaction, and the liquefaction level of the foundation is generally slight to moderate. .
1.2.2 Types and distribution of geological disasters
There are many types of geological disasters in Jinan, especially sudden geological disasters ranking first, focusing on collapses, landslides, debris flows, ground Geological disasters such as collapse and ground fissures. Collapses, landslides, and debris flows are mainly concentrated in the southern mountainous areas and piedmont areas, and are mostly caused by human engineering activities. Ground subsidence and ground fissures are mainly distributed in the eastern region of Jinan and scattered in other areas. They are mostly caused by human mining activities such as coal mines and iron ores and the large-scale exploitation of groundwater.
1.3 Evaluation of suitability for engineering construction
The stratigraphic distribution in Jinan is generally distributed in an east-west direction, and its suitability for engineering construction has an obvious zonal phenomenon. According to the difficulty of foundation treatment for engineering construction and the economy of engineering construction, engineering geological conditions can be divided into four categories: suitable areas, more suitable areas, poor suitability areas and unsuitable areas.
1.3.1 Suitable area
The suitable area is mainly distributed in the middle of the work area, spreading in an east-west direction, and is a piedmont alluvial plain or an intermountain slope alluvial deposit. The stable engineering geological environment area formed. This area is suitable for the construction of multi-story buildings and high-rise buildings. Multi-story buildings can use natural shallow foundations. Generally, small high-rise buildings can use natural foundation raft foundations. High-rise buildings can use deep foundation pit excavation, raft foundations or box foundations. .
1.3.2 More suitable area
The more suitable area is divided into three sections. The southern part is mainly distributed in the mountain valleys and is suitable for the construction of multi-story buildings and high-rise buildings, but it should be considered Impact on the geological and landform landscape; the central part is located in the contact area between the piedmont alluvial plain and the Yellow River alluvial plain, which is suitable for the construction of multi-story buildings. Natural foundation raft foundations can be used, and high-rise buildings can use pile foundations; the northern part is located in the area north of the Yellow River. It is suitable for the construction of multi-story buildings. Natural foundation raft foundation or composite foundation can be used. It is not suitable for the construction of high-rise buildings.
1.3.3 Poor suitability area
The poor suitability area is divided into two areas. The southern area is located in the low mountain and hilly area with a terrain slope greater than 30°; the northern area is located in the soft soil distribution area on both sides of the Yellow River. , multi-storey buildings in this area can use pile foundations and are not suitable for the construction of high-rise buildings.
1.3.4 Unsuitable construction areas
The unsuitable construction areas are scattered scattered, and the southern part is located in the area prone to geological disasters, especially areas where landslides and debris flows have great harm to people's lives and property; others The area is a goaf subsidence area, which is highly destructive to buildings.
2 Water Environment Quality Assessment
2.1 Current Status of Groundwater Pollution
2.1.1 Changes in Groundwater Quality in Jinan Region
In recent years, with the With the intensification of human activities and the increase in mining volume, the quality of karst water in Jinan has gradually deteriorated. Especially since the 1980s, the content of chemical components in karst water has increased rapidly. The salinity of karst groundwater in Emeishan Water Plant in the western suburbs in 2004 was 1.53 times that in 1959, and the total hardness was 1.22 times and 25.34 times higher than that in 1959. The groundwater quality in the refinery area was poor, and oil pollution was detected. The hardness of some machine well water, The mineralization and other indicators exceed the drinking water standards; the mineralization in the urban area in 2004 was 1.321 times that in 1958, the total hardness was 1.114 times, Cl- was 4.43 times and 11.84 times; the mineralization of groundwater in the eastern suburbs in 2004 The hardness is 2.09 times that of 1958, the total hardness is 1.46 times, and the total hardness is 7.75 times.
2.1.2 Current status of karst water pollution
Karst water pollution is mainly conventional ion pollution (including total hardness, total dissolved solids, nitrate, nitrite, sulfate, etc.) . In Jinan area, the nitrate and total exceedance rate is 1.6, the total dissolved solids exceedance rate is 3.2, the exceedance rate is 4.8, and the total hardness exceedance rate is 12.9. The hardness, mineralization, and maximum exceeding-standard multiples are 3.0 times, 2.5 times, and 4.8 times, indicating that the groundwater has suffered industrial pollution. The pollution of the five toxic elements (phenol, cyanide, As, Cr6+, and Hg) is relatively light, with only point pollution at the location of industrial and mining enterprises. Heavy metal ions (Cu, Pb, Zn) pollute natural water with low content. Oil pollution is mainly distributed near refineries in the eastern and western suburbs.
2.2 Groundwater quality evaluation
Based on the comprehensive evaluation, groundwater quality can be divided into: ① Areas with good water quality. It is widely distributed from the exposed areas of low hilly limestone in the southern suburbs to the hidden areas in the north. The groundwater type is mainly HCO3-Ca type. The hardness is generally less than 400mg/L, and the salinity is generally less than 500mg/L. All water management indicators are consistent with drinking water. The water quality standard is good and suitable as a domestic or industrial water supply source. ②Area with better water quality.
Distributed on the periphery of areas with poor water quality and connected to areas with better water quality. None of the components of the groundwater exceeds the groundwater quality level III standard and can be used as a centralized water supply source. ③Area with poor water quality. Mainly distributed in Houweihua Village, Houlongwo Village, Political Science and Law School and other places. In addition, the eastern and western suburbs are distributed in points in Budong, Armed Police Hospital, Shaoer, Beiru and other places. Some items in the groundwater exceed the quality of drinking water. Standard, suitable for farmland irrigation and industrial water, but needs to be treated when used as a drinking water source. ④Area with extremely poor water quality. It is only distributed in the Jingjiagou Village area. The comprehensive evaluation is a grade V water distribution area. The groundwater is mainly seriously polluted by industry and agriculture and is not suitable for drinking.
2.3 Analysis of the reasons for spring water outage
With the urban development, the demand for water resources has increased year by year, causing the water level to decline year by year. The spring water outage has not only affected the tourism industry of Jinan City , and affects the water quality of Daming Lake and Xiaoqing River. The reasons for spring water cutoff are as follows: ① Artificial mining is the main reason for spring water cutoff. Since the late 1960s, the exploitation of karst groundwater has increased year by year, and it is an indisputable fact that large-scale exploitation of groundwater has caused springs to stop flowing. In the 1950s and 1960s, the amount of groundwater extraction was only (4.7-12.6) Since the springs stopped flowing for the first time in the dry season in 1972, since the 1990s, the total production volume of water plants and industrial wells in the eastern suburbs, western suburbs, urban areas and industrial wells has been basically stable at around 55×104m3/d. ② As the city expands, the direct supply area decreases, and the southern expansion of the urban area results in a decrease in spring area supply. ③ The amount of recharge from indirect recharge areas decreases, and the amount of surface water recharge from reservoirs built in the southern mountainous areas decreases. ④Climate change and decrease in precipitation. ⑤The impact of excessive mining and excavation on the geological environment.
3 Long-term plan for the development of geothermal resources
The caprock of the geothermal field in the northern part of the work area is the Quaternary and Neogene systems of the Cenozoic, the Permian and Carboniferous systems of the Paleozoic; the heat storage is Middle and Lower Ordovician limestone; normal geothermal heat flow is its main heat source. The boundary of the geothermal field and the deep internal faults are the channels for the communication between geothermal water and deep heat sources. The burial depth of the heat storage roof ranges from 200m to 200m from south to north. The southern side of the Qiguang fault increases to nearly 3000m.
3.1 Economic Geothermal Resource Exploitation Area
The heat storage depth in this area is less than 2000m, which is easy to exploit and has good economic benefits. The area is further divided into four sub-areas based on the 500m burial depth difference: Sub-area I is located in the southern limestone strip of the geothermal field and the Taoyuan-Dongjia area in the east. The burial depth of the thermal storage roof is less than 500m, and the suitable well depth is less than 700m. , it is estimated that the heat storage temperature is 25-40°C; sub-region II is located in the periphery of the limestone strip, Qihe Shimenzhang-Jiu Qihe-Beijiao Forestry-Jinjia-Yawangkou, and is distributed in a nearly east-west direction, with heat storage The roof burial depth is 500 to 1000m, the suitable well depth is 700 to 1200m, and the heat storage temperature is estimated to be 40 to 50°C; Sub-area III is located in the area north of Balizhuang-Jiaobin-Biaobaisi-Sungeng-Qingning-Yaoqiang Airport. Distributed in an arc-shaped strip, the thermal storage roof is buried 1000-1500m deep, and the suitable well depth is 1200-1700m. The thermal storage temperature is estimated to be 50-65°C; Sub-area IV is located in the Biaobaisi-Sungeng-Huihe area, and the thermal storage roof is buried The depth is 1500~2000m, the suitable well depth is 1700~2200m, and the thermal storage temperature is estimated to be 65~80℃.
3.2 Sub-economic geothermal resource mining area
This area is located on the south side of the Qiguang fault, with a thermal storage depth of 2000-3000m. The mining technical conditions are difficult and the economic conditions are unreasonable. Due to the large burial depth of the thermal reservoir, the thermal storage temperature is relatively high. It is estimated that the thermal storage temperature is 80-90°C and the well depth is 2200-3200m.
4 Analysis of geological environmental protection of urban development space
4.1 Construction of underground rail transit sections and spring water protection
4.1.1 Analysis of engineering conditions
The underground section of the first phase of Jinan Rail Transit Line 1 is planned to start from Jiefang Bridge in the east and end at Weijiazhuang in the west. It is located in the center of bustling Quancheng. The underground section is about 3000m long. The underground section of the light rail is 16m deep and the tunnel construction height is 6.4m.
Among them, the underground section of Qingtuan Road-Qinglong Bridge is about 1700m long, with four major springs distributed on both sides.
The thickness of the Quaternary system in the underground section of the light rail is 10.7-21.52m. The lithology is mainly mixed fill soil, silty clay mixed with gravel and residual soil. Underneath it is the diorite rock mass, and the bottom burial depth is 43.56m. ~82.49m, and further downward is Ordovician-Cambrian limestone.
Based on the different groundwater occurrence media, the pore water along the line can be mainly divided into loose rock pore water: the water inflow in a single well is less than 500m3/d; intrusive rock weathering fissure water: closely related to the upper loose rock pore water , the water output of a single well is less than 100m3/d and the three water-bearing rock groups of fissure karst water: the water inflow of a single well can reach 5000~10000m3/d, and the groundwater level is closely related to precipitation.
In areas where diorite is thicker, there is a diorite aquifer. The hydraulic connection between shallow pore-fissure water and deep fissure karst water is weak, but in local areas, such as Wulongtan and Pearl In areas such as springs, affected by factors such as structures and fissures, deep karst water can penetrate the diorite and form certain hydraulic connections with pore-fissure water. The formation of springs is closely related to topography, stratigraphy, geological structures and hydrogeological conditions.
4.1.2 Analysis of the relationship between spring water and pore-fissure water
①The supply sources of karst water and pore water are different, and the runoff and discharge methods are inconsistent; ②The karst water and pore water levels near the spring area Inconsistent; ③ There is a big difference in water richness between shallow pore and fissure water and deep karst water: along the line from Jiefang Bridge to Pulimen in the urban area, the water inflow from a single well of karst water is more than 5000m3/d, and from the north of Pearl Spring and Wulongtan to Daming Lake In this area, the water inflow volume of a single well is between 1000 and 5000m3/d, while the water inflow volume of a single well of shallow pore-fissure water along the line is generally less than 500m3/d, and the drop depth is large; ④ The water chemical characteristics are different, and the karst water quality is good. It complies with drinking water quality standards. Due to artificial pollution, pore-fissure water has complex and changeable water chemistry types and high salinity.
4.1.3 Suggestions for the construction of underground sections
Karst spring water and Quaternary pore-fissure water have different replenishment, diameter and drainage conditions. The water-bearing medium, water richness, water quality, There are differences in water levels. The main source of spring water supply is the vast southern mountainous area. Such a large spring flow cannot come from the Quaternary aquifer. It can be seen that the formation of Jinan spring water is extremely complex. It is speculated that the spring water exposure is related to the local structure related.
In the Minghu Road area, the limestone (marble) is buried deep. Therefore, without considering the passenger flow, the underground section of the track project is suitable to be located on Minghu Road.
4.2 Analysis of geological environment protection
4.2.1 Analysis of the relationship between urban expansion and spring water protection
4.2.1.1 Impact of urban expansion evolution on recharge
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The urban expansion direction of Jinan is mainly towards the east, southeast, south and southwest. The fastest expansion of urbanization to the south has occurred since the 1980s, mainly to the Ordovician limestone area in the south. The Ordovician limestone surface karst in this area 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 age. The urban runoff coefficient was 0.5 in the 1960s and increased to 0.9 in the 1990s. The increase in runoff has reduced underground infiltration recharge, and most precipitation has been lost. Urban expansion and hardening of the ground are among the factors causing the reduction in spring water supply.
4.2.1.2 Prediction of the impact of eastward and westward expansion on groundwater recharge
The lower reaches of the eastern industrial belt are the Baiquan-Wujia water source, which is less than 3 km east of the Huangtuya water source; Therefore, the large-scale planning and construction of the eastern industrial belt will inevitably directly affect the allowable mining volume of the Baiquan-Wujia water source and Huangtuya water source. It is predicted that the construction of the eastern industrial belt will reduce groundwater recharge by 4.09×104m3/d in the next year.
(1) Western New City
The Second Ring West Road-Yufu River area is located at the front edge of the piedmont sloping plain. The development and construction of this area should be in the contact zone between igneous rock and limestone. The north is suitable, that is, the north of Duandian-Xihongmiao-Dayangzhuang-Danshantun-Xiaojinzhuang; Dangjiazhuang area: located upstream of the direct supply area, development should be controlled and existing sewage discharge points should be effectively managed; The Dajianggou-Nankangzhuang line is located in a direct recharge area and is closely related to urban groundwater. Sewage seepage will have an impact on the quality of karst water, so this area is not suitable as a planning area.
(2) Changqing University Campus
The downstream Qiaozili and Lenzhuang water sources are less than 5 km away from the planned land; they receive direct recharge from atmospheric precipitation and runoff downstream, forming the Jixi It is an important supply source for Qiaozili water source, Lenzhuang water source, Dayangzhuang water source and Emeishan water source. Therefore, the planned construction will have a greater impact on groundwater recharge, and the annual infiltration recharge is expected to be reduced by 6.394×107m3.
(3) Changqing Area
The Changqing Planning Area is located in the west of Jinan Spring Area, in the Qiaozili and Laozhangzhuang areas in the northeast of Changqing. It has rich groundwater resources and single wells. The water volume is about 104m3/d, which has the potential for concentrated mining. The mining volume should be controlled below 10×104m3/d. Large-scale development and construction in the east and southeast of Changqing is not suitable, and ecological protection should be the leading development direction. A large area of ??limestone is exposed in the low mountainous and hilly areas in the south. It is a direct supply area for karst water in Jinan springs. Direct discharge of sewage is strictly prohibited. At the same time, the urban planning area in the first-level protection zone should be minimized, focusing on protection from Ping'an Dian to Pan in the west. Village, along the Yufu River Valley to Fengqi, from the direct supply area south of Dayangzhuang-Liuchangshan-Yingxiongshan-Yangtouyu-Guodian line, so as to avoid reducing the supply of springs.
4.2.1.3 Determination of the location of the Southern Control Red Line
Comprehensive analysis of past data shows that in order to avoid development and construction affecting spring water supply and promote the sustainable development of Jinan City, the "Southern Control" should be protected The direct supply area south of the Pingandian-Pancun-Yufu River Valley-Fengqi-Dayangzhuang-Liuchangshan-Yingyingshan-Yangtouyu-Niuwang line.
4.2.2 Geological environment protection measures
4.2.2.1 Small watershed management measures
Implement the principle of “protection during development”: take effective measures Prevent siltation and occupation of valleys, build dams, and stop approving development and construction projects in southern mountainous areas. Implement bioengineering, increase afforestation area, and protect natural vegetation.
4.2.2.2 Water environment protection measures
The limestone in the low hills and hills in the southern part of the Jinan spring area is exposed over a large area and is a direct supply area for karst water. Some valley sections are flooded by alluvial deposits. It is covered by a layer of water, but the thickness is small. The karst on the surface is developed. Pollutants can easily seep down and pollute the groundwater in this area. It is a first-level protected area. Direct discharge of sewage should be strictly prohibited, and the urban planning area in the first-level protected area should be reduced as much as possible.
4.2.2.3 Geological and geomorphological landscape protection analysis
Carbonate rock formations are widely distributed in Jinan area, and the main minerals include limestone, dolomite, iron ore, granite, etc. Iron ore mining sites are mainly located around urban areas; limestone and dolomite mining sites are mainly distributed in vast low-mountain and hilly areas, mainly in strips near the piedmont areas. Existing quarrying points or stopped quarrying points have caused varying degrees of damage to the landforms and vegetation, affecting the image of the city. The main manifestations are: ① destroying vegetation, exacerbating water and soil erosion, and affecting the supply conditions of karst water; ② destroying landscapes, leaving behind steep walls, dangerous cliffs, and debris, which can easily induce geological disasters such as collapses, landslides, and debris flows; ③ affecting water quality.
4.2.2.4 Feasibility analysis of recharge and source replenishment project
(1) Analysis of recharge and source replenishment conditions
Existence of storage space: Jinan spring area underground karst development, the total discharge volume is large, and the annual variation of the groundwater level is small, there is groundwater space for regulation and storage; it has leakage conditions: the rivers and valleys in the direct recharge area have good leakage conditions, providing a favorable place for replenishing the source; sufficient Water source: Jinan is endowed with unique advantages, including local surface water resources, passenger water resources from the Yellow River, and, after the implementation of the South-to-North Water Diversion, passenger water from the Yangtze River.
Many reservoirs have been built in the mountainous area in the southern part of the Jinan spring area, with a maximum storage capacity of about 1.8×108m3. It can be seen that there is a large amount of surface water resources in the indirect recharge area that can be used to replenish the source; favorable geological conditions: According to Crouching Tiger on March 12, 2002 The water recharge test from Shan Reservoir proved that the Yufu River Basin has a replenishing effect on spring water.
(2) Analysis of source replenishment amount
Analysis of source replenishment amount of Yufu River: leakage amount per unit length of the Zhangxia limestone channel in the indirect recharge area (1.36~1.543)×104m3/ (d·km), the length of the Yufu River limestone section south of Pancun is calculated as 10.5km, and the amount of water recharge from the reservoir can be designed to be less than 14×104m3/d.
Analysis of source replenishment of Beishahe River: The south of Qiandayandong 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 between Qiandayanqiao and Weizhuangxi is 4.5km long. , the calculated unit leakage volume is 1.4225m3/(d·km). The length of the Weizhuang South Limestone Section is 6.76km, and the supply volume of the Beishahe River is designed to be 9.6165×104m3/d.
(3) Water quality demonstration
The source water of the Yellow River contains large amounts of sand and is not suitable for direct recharge. However, after precipitation, the water of Yuqing Lake and Queshan Reservoir and the Wohushan Reservoir in the south (Jinxiuchuan Reservoir) water, the physical indicators meet the requirements for recharge water. The hardness is 182.26~286.4mg/L, the pH value is between 7.4~8.2, the salinity is lower than the content and does not exceed the drinking water quality standard, the Mn ion content is less than 0.1mg/L, the H2SiO2 content is less than 20mg/L, and the dissolved iron The content is less than 0.5mg/L and Na+ is less than 50mmol/L, which basically meets the requirements as recharge water. The five poisonous elements and heavy metals in the reservoir water did not exceed the standard, and it also met the water requirements for water replenishment.
(4) Selection of source replenishment areas
①Pushuiquan-Zhongjing regulation and storage replenishment area: Mengjia-Shiheling, Zhongjing-Xiajing, Pugshuiquan-Jingshidong Road There are three gullies with a catchment area of ??31.7km2. The recharge in this area plays an important role in replenishing the karst water in the northern high-tech development zone, reducing the plunder of spring water supply in the eastern suburbs, improving the deteriorated ecological environment nearby, and playing an important role in restoring spring water and slowing down the underground water supply in the eastern suburbs high-tech development zone. The continued expansion of the landing funnel is of great significance. ② Xinglong-Fenshuiling Source Replenishment Area: There are six valleys including Xinglong, Xiaolingzi, Wataojing, Xiezishan, Huashanyu and Beishiyu. They are located upstream of the four major spring groups and are close to the spring groups. This area has direct connections with the four major spring groups. connect. Therefore, the replenishment source in this area has a direct recharge effect on the spring water. ③Shaoer-Lashan source replenishment area: Distributed in the Lashan River, source replenishment in this area is conducive to reducing the invasion of spring water supply by back-well mining in the western suburbs. ④Yufu Hezhaiertou-Luoer Buyuan Area: This area is a typical area where surface water recharges karst water, which is conducive to reducing the invasion of spring water supply by the western suburbs water plant. The main source river is Yufu River, with Wohushan Reservoir and Jinxiuchuan Reservoir built in its upper reaches. ⑤Beishahe Gushan Barrage-Pipa Mountain Replenishment Area: The regular release of water from Yuezhuang Reservoir to replenish the source is of great significance for improving the geological environment of the water source area to be exploited. The Beisha River regulation and storage area is mainly located between the Gushan Barrage and Pipa Mountain. Surface water leakage in this section is serious, and the Dongfeng Reservoir is built in the river, which provides favorable conditions for replenishing the source. ⑥Baiquan Spring Area Colored Stone-Ganggou Replenishment Area: With the planning and construction of the eastern industrial belt, the urban built-up area in Baiquan Spring Area is increasing year by year, and the number of enterprises and population is increasing, which affects the supply of downstream water sources. Colored Stone-Ganggou Replenishment Area The supplementary source is located upstream of the water source and is of great significance to improving the geological environment of the Baiquan area. Rivers such as Juye River, Ganggou River, and Zhangjin River are distributed in the source-supplementing area.
(5) Recharge engineering measures
①Linear recharge: Treat existing valleys to allow surface water to infiltrate naturally along the valleys. ② Infiltration of reservoirs and ponds: Reservoirs and ponds accumulate a certain amount of water, which not only increases a certain infiltration pressure but also prolongs the infiltration time. Moreover, the infiltration volume is large. The reservoirs that have been built can be used after dredging the reservoir area. Retention dams can be built in areas favorable for water storage to increase the infiltration of surface water. ③Well point injection method: Lay out large-diameter seepage wells and use free water heads or water pumps to directly inject into the karst aquifer.
It is recommended that the Jinxiuchuan Reservoir release water to replenish the southern part of the city, the Wohushan Reservoir release water along the Yufu River to replenish the western suburbs and southwest of the city, and the Yuezhuang Reservoir release water along the Beisha River to use for newly opened water sources in the western suburbs. In the Dongjiao Development Zone, the Langmaoshan Reservoir is used to replenish the source of the Baiquan Spring Area. In years of continuous drought, the Yellow River can be diverted to replenish the source.
4.2.2.5 Analysis of sustainable utilization of karst groundwater and spring protection
In order to maintain sustainable utilization of karst groundwater resources and protect springs in Jinan spring area, it is necessary to rationally develop and utilize water resources and implement quality separation Water supply, make full use of guest water resources, implement recharge and ecological environment protection in southern mountainous areas.
(1) Reasonable exploitation of groundwater for domestic and high-precision industrial water use
In the Jinan spring area, under the condition that the spring water level is not less than 27.5m during the dry season, the amount of replenishment in the southern mountainous area is 25 ×104m3/d, the recoverable volume of karst water in Jinan spring area is 33.5×104m3/d, and the spring water reuse is 5×104m3/d. The total resources of the East Baiquan Spring Area in Jinan Spring Area are 39.523×104m3/d. In addition to agricultural mining and coal mine drainage, the water supply from the Baiquan, Wujia and Huangtuya water sources is 28.29×104m3/d. In the west of the spring area - Xiaoshui source area, some boreholes flow freely during the high water period, and the water level varies by 2 to 4m. The local industrial and agricultural mining volume is small, and the water source area is still in a natural state. It is recommended to increase the mining volume by 8×104m3/d. A total of 69.79×104m3/d high-quality groundwater resources can be used for domestic and high-tech industrial water. If domestic water is calculated as 120 liters/(day·person), high-quality karst groundwater resources can meet the domestic water needs of 5.8 million people.
The self-provided wells of industries in the periphery of the urban area are closed to reduce the supply of spring water stolen by peripheral mining. On the premise of saving water, agricultural irrigation mainly uses surface water and restricts the use of karst groundwater. The "North Cross" planning area is a potential area for geothermal resource development. The underground hot water supply conditions are poor, so the amount of mining should be limited. The water supply source can be the Yellow River water from Queshan Reservoir.
(2) Make full use of guest water resources as industrial water sources
For industrial water with low water quality requirements, surface water resources should be the main source, such as Yuqing Lake and Queshan Reservoir. The water supply volume is 80×104m3/d, the reclaimed water utilization is 23×104m3/d, and the air defense trunk water is 4.0×104m3/d. The total water supply of surface water and groundwater is 177.79×104m3/d. The insufficient water can be supplemented by water diversion from the Yellow River and the Yangtze River. After the implementation of the South-to-North Water Diversion, the karst groundwater in the Baiquan-Wujia water source area can all be used for domestic drinking water supply. The Jinan Iron and Steel Plant, Huangtai Power Plant, Fertilizer Plant, Heavy Machinery Plant and other large water users in the eastern suburbs will be closed to exploit groundwater and use Yellow River water and Yangtze River water. As a water supply source, according to the plan, the designed storage capacity of the East Lake Reservoir is 5700×104m3, and the daily water supply is 40×104m3/d.
(3) Comprehensive management and recharge in the southern mountainous areas
Wohu Mountain, Jinxiuchuan, and Yuezhuang surface reservoirs are used as ecological water, and the rivers and valleys in the southern mountainous areas are dredged and dams are built. After comprehensive treatment, water will be released to the Xinglong-Shiliuli River, Yufu River, and Beisha River to replenish the source; the eastern suburbs currently lack water replenishment sources, and in the future, the water from the East Lake Reservoir can be used to replenish the source in the area east of Longdong. If the high-tech development zone and its Replenishing the source in the southern range is very beneficial to restoring spring water.
5 Conclusion
Starting from the geological environmental conditions related to Jinan's urban construction, this paper discusses it from many aspects, aiming to provide reference suggestions for Jinan's urban construction. However, many issues related to urban construction still require further exploration. It is hoped that relevant departments and industries can work together to provide valuable opinions on Jinan's urban construction.