Evaluation method based on overall impervious effect of landscape lake body

Abstract

The invention discloses an evaluation method based on the overall impervious effect of a landscape lake body, and the method comprises the following steps: draining landscape lake water, monitoring the water level change during the period, and measuring the water level change of an evaporation barrel; injecting water into the lake, injecting water to 1 / 3 of the maximum water depth for the first time, injecting water to 1 / 3 of the maximum water depth after 24 hours, stopping injecting water, starting to record the initial water level, and recording the water level after 24 hours; measuring and calculating the evaporation capacity and the water seepage capacity of the lake area: injecting water to 2 / 3 of the maximum water depth again, recording the water level at the moment, and recording the water level after 24 hours; the water injection interval is 24 hours, the water levels before and after water injection are recorded, and the steps are repeated; the water level difference and the daily leakage ratio before and after each time of water injection are calculated and compared with the standard threshold value of the daily leakage ratio of the artificial lake; the lake body anti-seepage treatment effect can be effectively verified, and guidance is provided for formulating a seepage control scheme in the later period.

Description

Technical Field

[0001] The invention relates to an evaluation method for anti-seepage effect, and in particular to an evaluation method based on the overall anti-seepage effect of a landscape lake. Background Art

[0002] The normal water storage level of landscape lakes is usually higher than the surrounding groundwater level. If there are problems with anti-seepage measures, after water storage, due to the difference in water head, the water in the lake area will continue to leak downstream through the gaps between soil particles. Over time, leakage channels will be formed, resulting in a large amount of water loss. The leakage of lake water affects the groundwater level around the lake, causing uneven settlement of existing shallow-buried foundation buildings, and in severe cases, deformation, cracking, or even damage to the building structure; the large-scale loss of water not only causes a waste of water resources, but also affects the water exchange of the artificial lake, leading to the deterioration of the overall ecological environment. Summary of the invention

[0003] In view of this, the purpose of the present invention is to overcome the defects in the prior art and provide an evaluation method based on the overall anti-seepage effect of the landscape lake, which can effectively verify the anti-seepage treatment effect of the lake and provide guidance for the formulation of subsequent seepage control plans.

[0004] The present invention provides an evaluation method based on the overall anti-seepage effect of a landscape lake, comprising the following steps:

[0005] S1: Drain the landscape lake, clean up the debris in the lake, repair the defects inside and outside the lake, temporarily block the reserved holes and water inlets and outlets, prevent the vent pipe and drainage gate from leaking, and then soak the inner wall of the landscape lake;

[0006] S2: Install electronic water level gauge, evaporation barrel, rain collector and water level measuring needle to monitor water level changes during the period and measure water level changes in the evaporation barrel;

[0007] S3: Fill the lake with water, fill it to 1 / 3 of the maximum water depth for the first time, start recording the initial water level, and then record the water level after 24 hours;

[0008] S4: Measure and calculate the evaporation and seepage of the lake area, calculate the daily seepage ratio and compare it with the standard assessment reference value, and conclude that the daily seepage ratio is the ratio of daily seepage to total water volume;

[0009] S5: Fill water again to 2 / 3 of the maximum water depth, record the water level at this time, and record the water level after an interval of 24 hours; repeat step S4 until the water is filled to the maximum water depth, and record the water level before and after the water filling after an interval of 24 hours, and repeat step S4;

[0010] Further, in step S4, the evaporation amount is the average of the actual evaporation bucket calculated amount and the amount calculated by the following empirical formula:

[0011]

[0012] Where:

[0013] E is 20m 2 Evaporation rate of evaporation pond (mm / d, which can be approximated as evaporation rate of lake surface);

[0014] e0 is the saturated water vapor pressure at the water surface temperature (3170Pa = 31.7HPa at 25℃);

[0015] e 150 is the actual water vapor pressure 150 cm above the water surface (the saturated water vapor pressure at that temperature multiplied by the relative humidity, hPa);

[0016] W 150 - Daily average wind speed at 150cm above the water surface.

[0017] Further, in step S4, the lake area seepage volume is calculated by the following formula:

[0018] q=A1[(E1-E2)-(e1-e2)]

[0019] Where:

[0020] q-water seepage [L / (m 2 .d)];

[0021] A1- Lake surface area m 2 ;

[0022] E1-initial reading of electronic water gauge in landscape lake (mm);

[0023] E2-the final reading of the water level gauge 24 hours after E1 (mm);

[0024] e1- Initial reading of the water level probe in the water tank (mm);

[0025] e2- Reading of the water level probe in the water tank 24 hours after e1 (mm).

[0026] Further, it is characterized in that: in step S4, water is injected at a uniform rate for 24 hours at a time, and the daily water seepage ratio is calculated by the following formula:

[0027] Q 比n =q 渗n / q 蓄n

[0028] q 蓄n =q 蓄(n-1) +V 注n -0.5q 渗n -q 蒸n

[0029] Among them, Q 比n is the daily water seepage ratio of the nth water injection test, V 注n is the nth single water injection volume, q 渗n is the daily water seepage volume for the nth time of 24 hours of rest, q 蒸n is the evaporation amount within 24 hours during the nth water injection.

[0030] The beneficial effects of the present invention are as follows: the present invention discloses an evaluation method based on the overall anti-seepage effect of a landscape lake, which provides a simple, convenient and efficient approach, can effectively solve the problem of insufficient leakage monitoring of existing landscape lakes, is conducive to subsequent rectification, improves work efficiency, shortens construction period, and has accurate detection, which is conducive to long-term maintenance in the later stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0032] Figure 1 It is a cross-sectional view of the water level gauge arrangement in the present invention. DETAILED DESCRIPTION

[0033] In this embodiment, an evaluation method based on the overall anti-seepage effect of the landscape lake body includes the following steps: S1: draining the landscape lake water, cleaning up the debris in the lake, repairing the defects inside and outside the lake, temporarily blocking the reserved holes and water inlets and outlets, so that the vent pipe and the drainage gate do not leak, and then soaking the inner wall of the landscape lake; S2: installing an electronic water level gauge, an evaporation barrel, a rain collector and a water level probe to monitor the water level changes during the period and measure the water level changes in the evaporation barrel; S3: filling water into the lake, the first filling to 1% of the maximum water depth / 3, start recording the initial water level, and record the water level after an interval of 24 hours; S4: measure and calculate the evaporation and seepage of the lake area, calculate the daily seepage ratio and compare it with the standard assessment reference value, and conclude that the daily seepage ratio is the ratio of daily seepage to total water volume; S5: inject water again to 2 / 3 of the maximum water depth, record the water level at this time, and record the water level after an interval of 24 hours; repeat step S4 until the maximum water depth is injected, wait 24 hours, and record the water level before and after the injection, and repeat step S4;

[0034] In step S4, water is injected at a uniform rate for 24 hours at a time, and the daily water seepage ratio is calculated by the following formula:

[0035] Q 比n =q 渗n / q 蓄n

[0036] q 蓄n =q 蓄(n-1) +V 注n -0.5q 渗n -q 蒸n

[0037] Among them, Q 比n is the daily water seepage ratio of the nth water injection test, V 注n is the nth single water injection volume, q 渗n is the daily water seepage volume for the nth time of 24 hours of rest, q 蒸n is the evaporation amount within 24 hours during the nth water injection, q 蒸 According to the empirical formula According to the test, the evaporation liquid level is half of the water injection depth; V 注 This can be obtained by installing a flow meter at the water injection pump. By controlling the water injection to about 24 hours, due to the increase in water pressure components, 0.5q 渗 The daily seepage during water injection can be roughly estimated to avoid large errors. The real-time water storage capacity of the artificial lake is V 注 -0.5q 渗 -q 蒸 , which is also the first water storage capacity q 蓄1 Of course, the real-time water storage capacity of the second injection is V 注2 -0.5q 渗2 -q 蒸2 , the second total water storage is the sum of the previous two real-time water storage, then q 蓄2 =V 注 -0.5q 渗 -q 蒸+ V 注 -0.5q 渗 -q 蒸 , then Q 比2 =q 渗2 / q 蓄2 , and the daily leakage ratio of the third water injection can be calculated by analogy. This method can accurately calculate the leakage ratio and compare it with the reference value, and provide relevant suggestions and measures to meet the requirements of water storage and anti-seepage. For example, taking the landscape lake of the R06-3 / 04 and R06-2 / 03 park project in the R standard zone of the honeycomb city in Caijia Group, Beibei District, Chongqing as an example, the artificial lake has a wide water area of ​​8900m 2 The maximum water depth of the designed lake is about 2m, and the water storage capacity is about 15,000m3. The landscape lake of this project is a half-cut and half-filled structure, and the plane projection area of ​​the anti-seepage treatment range is about 12,000m 2 . Lake body anti-seepage structure: compacted soil thickness ≥ 30cm, coarse sand cushion layer 20cm, composite geomembrane thickness 0.1cm. Compacted clay layer ≥ 94%, clay layer thickness 1m in backfill area, clay layer thickness 0.3m in excavation area. The artificial lake is designed to have a water level of 279.80m and a maximum water depth of 2m. Water is injected into the lake in three times, each time for 1 / 3 of the designed water depth, and the water level rise rate does not exceed 2m / d during injection.

[0038] (1) For the first water storage, the test group was set to 3 groups. The bottom elevation of the electronic water gauge 1 was 278m, and the target water level for the first water storage was 278.30m. The initial observation value was 278.29m. The water level change was observed continuously for 24 hours. The end observation value was 278.28m. The water level dropped by 1cm in 24 hours. The bottom elevation of the electronic water gauge 2 was 277.983m, and the target water level for the first water storage was 278.30m. The initial observation value was 278.30m. The water level change was observed continuously for 24 hours. The end observation value was 278.30m. The bottom elevation of the electronic water gauge 3 was 277.78m, and the target water level for the first water storage was 278.30m. The initial observation value was 278.29m. The water level change was observed continuously for 24 hours. The end observation value was 278.28m. The water level dropped by 1cm in 24 hours. After calculation, the daily leakage ratio was not large. To sum up, it shows that there is leakage at the bottom of the artificial lake, but the leakage is not large and needs further observation in the future.

[0039] The wind speed and humidity measurement values ​​within 24 hours after the first water injection are shown in Table 1, and the evaporation bucket measurement values ​​are shown in Table 2.

[0040] Table 1 Wind speed and humidity measurement values ​​for the first water injection (frequency: once every two hours)

[0041]

[0042] Table 2 Measurement values ​​of the first water filling evaporation bucket

[0043]

[0044] (2) Second water injection

[0045] The bottom elevation of electronic water gauge 1 is 278m, and the target water level for the second water storage is 278.80m. The initial value of the observation is 278.79m, and the water level change is continuously observed within 24 hours. The end value of the observation is 278.76. The water level dropped by 3cm in 24 hours. The bottom elevation of electronic water gauge 2 is 277.983m, and the target water level for the second water storage is 278.80m. The initial value of the observation is 278.803m, and the water level change is continuously observed within 24 hours. The end value of the observation is 278.783, and the water level dropped by 2cm in 24 hours. The bottom elevation of electronic water gauge 3 is 277.78m, and the target water level for the second water storage is 278.80m. The initial value of the observation is 278.78m, and the water level change is continuously observed within 24 hours. The end value of the observation is 278.75, and the water level dropped by 3cm in 24 hours. After calculation, the daily leakage ratio is not large. This indicates that there is leakage at the bottom of the lake, but the amount of leakage is not large and needs further observation in the future.

[0046] The wind speed and humidity measurement values ​​within 24 hours after the second water injection are shown in Table 3, and the evaporation bucket measurement values ​​are shown in Table 4.

[0047] Table 3 Second water injection wind speed and humidity measurement values ​​(frequency: once every two hours)

[0048]

[0049]

[0050] Table 4 Measurement values ​​of the second water injection evaporation bucket

[0051]

[0052] According to Table 4, the average evaporation of the bucket is 0.24cm, and the evaporation value calculated by the empirical formula is 0.36cm. The evaporation amount is taken as the average value. After calculation, the daily leakage is relatively large, and it is necessary to continue to extend the observation. Subsequent observations found that the water level dropped from 278.79m to 278.62m, and the water level dropped by 17cm in 6 days, with an average daily drop of 2.83cm. The water level drop trend is obvious, and the daily leakage ratio continues to be large, exceeding the reference threshold.

[0053] Comprehensive subsequent continuous observations revealed that the landscape lake had excessive leakage and that there were leakage channels, which required further construction and treatment before further observation.

[0054] (3) Re-injection after repair

[0055] According to the previous water level monitoring results, the landscape lake was found to have serious leakage. After construction and repair, the water level was stored to the design water level of 279.76m. A 7-day continuous observation period was planned from March 1 to March 7, 2023 to monitor the changes in water level and leakage. Due to the on-site construction on the afternoon of March 4, the water level dropped, and then the water was replenished to the water level on March 3 on the 5th. Therefore, the water level changes on March 4 and March 5 were not considered, and the observation period was extended to March 9. The on-site measurement values ​​are shown in the following table.

[0056] Table 5 On-site observation of wind speed and humidity measurement values ​​(frequency: once every three hours)

[0057]

[0058]

[0059] Table 6 Water bucket evaporation measurement values

[0060]

[0061]

[0062] Table 7 Field observation test data record table

[0063]

[0064]

[0065] Table 8 Water level change table

[0066]

[0067] As can be seen from Table 7, except for the slightly heavier rainfall on March 7, which caused the water level to rise by 1 cm, the water level remained unchanged at 379.76m on the other five days. Although there was rainfall on March 1, 2, 6, 7, and 9, except for the slightly heavier rainfall on March 7, which caused the water level to rise, the rainfall and evaporation results on the other four days were similar, which confirms the result that the water level remained unchanged. Although there was rainfall during the observation period, the rainfall and evaporation results were close, and the on-site water level remained stable, indicating that the seepage of the landscape lake was within a reasonable range.

[0068] Phase I Overall Assessment

[0069] At 14:00 on October 4, 2022, water was added to the first stage target water level of 278.29m. By 10:00 on October 5, the water level had settled by 7cm in 20 hours. After the settlement was completed, water was added to 278.29m at 14:24 on October 5, and the first stage of water closure test was carried out. By 14:24 on October 6, the electronic water gauge reading was 278.21m, the water level dropped by 8cm, and the average evaporation of the water bucket was 0.57cm. After calculation, the leakage volume was 168.46m 3 The leakage is serious. After investigation by on-site construction personnel, it was found that the pipeline near the electronic water gauge 2 was broken, which caused the leakage.

[0070] After repairs by the construction party, water was added to the target water level and the sedimentation was completed within 24 hours. At 15:45 on November 1, the water level was replenished to the target water level of 278.29m. By 15:45 on November 2, the electronic water gauge reading was 278.28m, and the water level dropped by 1cm. The average evaporation value of the bucket was 0.69cm, and the evaporation value calculated by the empirical formula was 0.80cm. The evaporation was taken from the empirical formula result. After calculation, the leakage amount was 4.53m 3 , daily leakage is relatively small.

[0071] The second water injection in the first phase was completed at 13:30 on November 6, after 24 hours of sedimentation, to replenish the water to the target water level of 278.79m. By 13:30 on November 7, the electronic water gauge reading was 278.76m, and the water level dropped by 3cm. The average evaporation value of the bucket was 0.24cm. The evaporation value calculated by the empirical formula was 0.36cm. The average evaporation value was taken. After calculation, the leakage amount was 96.38m 3 .

[0072] Due to the excessive leakage after the second water injection, the observation was extended and it was found that from November 6 to November 12, the water level dropped from 278.79m to 278.62m, and the water level dropped by 17cm in 6 days, with an average daily drop of 2.83cm. There was no weakening trend in the water level drop. On November 12, due to the construction needs of the construction party, the water in the acrylic lake under the stand was pumped to the artificial lake, and the water level rose from 278.63m to 278.70m on November 13. From November 13 to November 30, the water level dropped from 278.70m to 278.32m, and the water level dropped by 38cm in 17 days, with an average daily drop of 2.23cm. The water level drop trend during this period was somewhat weakened. From November 30 to December 6, the water level dropped from 278.32m to 278.25m, and the water level dropped by 7cm, with an average daily drop of 1.17cm. The water level drop trend was obvious.

[0073] Based on the two water injection tests in the first phase and subsequent continuous observations, it was found that the seepage volume of the landscape lake was too large, the daily leakage ratio was large, it did not meet the standards, and there were leakage channels, which required subsequent construction treatment before further observation.

[0074] Phase II Overall Situation Assessment

[0075] According to the previous water level monitoring results, the landscape lake was found to have serious leakage. After construction and repair, the second phase of water injection test was carried out on February 26, 2023, and the water level was stored to the design water level of 279.76m. A 7-day continuous observation period was planned from March 1 to March 7, 2023 to monitor the changes in water level and leakage. Due to the on-site construction on the afternoon of March 4, the water level dropped, and then the water was replenished to the water level on March 3 on the 5th. Therefore, the water level changes on March 4 and March 5 were not considered, and the observation period was extended to March 9.

[0076] During the observation period, it can be seen that from February 26 to March 4, the water level remained unchanged at 279.76m for 7 consecutive days, and the water level dropped due to on-site construction in the afternoon of the 4th. After the water level was replenished to the original level in the later period, except for the slightly heavier rainfall on March 7, which caused the water level to rise by 1cm, the water level remained unchanged at 379.76m for the remaining 5 days. Although there was rainfall on March 1, 2, 6, 7, and 9, except for the slightly heavier rainfall on the 7th, which caused the water level to rise, the rainfall and evaporation results on the other 4 days were similar, which confirmed the result that the water level remained unchanged. Although there was rainfall during the observation period, the rainfall and evaporation results were close, and the on-site water level remained stable. After calculation, the daily seepage was relatively small, which met the standard requirements, and the seepage of the landscape lake was within a reasonable range.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for evaluating the overall anti-seepage effect of a landscape lake, characterized by: The following steps are involved: S1: Drain the landscape lake, clean up the debris in the lake, repair the defects inside and outside the lake, temporarily block the reserved holes and water inlets and outlets, prevent the vent pipe and drainage gate from leaking, and then soak the inner wall of the landscape lake; S2: Install electronic water level gauge, evaporation barrel, rain collector and water level measuring needle to monitor water level changes during the period and measure water level changes in the evaporation barrel; S3: Fill the lake with water, fill it to 1 / 3 of the maximum water depth for the first time, start recording the initial water level, and then record the water level after 24 hours; S4: Measure and calculate the evaporation and seepage of the lake area, calculate the daily seepage ratio and compare it with the standard assessment reference value, and conclude that the daily seepage ratio is the ratio of daily seepage to total water volume; S5: Fill water again to 2 / 3 of the maximum water depth, record the water level at this time, and record the water level after an interval of 24 hours; repeat step S4 until the water is filled to the maximum water depth, wait 24 hours, and record the water level before and after the water filling, and repeat step S4.

2. The method for evaluating the overall anti-seepage effect of a landscape lake according to claim 1, characterized in that: In step S4, the evaporation amount is the average of the actual evaporation bucket calculated amount and the amount calculated by the following empirical formula: Where: E is 20m 2 Evaporation rate of evaporation pond (mm / d, which can be approximated as evaporation rate of lake surface); e0 is the saturated water vapor pressure at the water surface temperature (3170Pa = 31.7HPa at 25℃); e 150 is the actual water vapor pressure 150 cm above the water surface (the saturated water vapor pressure at that temperature multiplied by the relative humidity, hPa); W 150 —Daily average wind speed 150 cm above the water surface.

3. The method for evaluating the overall anti-seepage effect of a landscape lake according to claim 2, characterized in that: In step S4, the lake seepage volume is calculated by the following formula: q=A1[(E1-E2)-(e1-e2)] Where: q-water seepage [L / (m 2 d)]; A1- Lake surface area m 2 ; E1-initial reading of electronic water gauge in landscape lake (mm); E2-the final reading of the water level gauge 24 hours after E1 (mm); e1- Initial reading of the water level probe in the water tank (mm); e2- Reading of the water level probe in the water tank 24 hours after e1 (mm).

4. A method for evaluating the overall anti-seepage effect of a landscape lake according to any one of claims 1 to 3, characterized in that: In step S4, water is injected at a uniform rate for 24 hours at a time, and the daily water seepage ratio is calculated by the following formula: Q 比n =q 渗n / q 蓄n q 蓄n =q 蓄(n-1) +V 注n -0.5q 渗n -q 蒸n Among them, Q 比n is the daily water seepage ratio of the nth water injection test, V 注n is the nth single water injection volume, q 渗n is the daily water seepage volume for the nth time of 24 hours of rest, q 蒸n is the evaporation amount within 24 hours during the nth water injection.

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