Presentation is loading. Please wait.

Presentation is loading. Please wait.

26 June 2012 Korea Rural Research Institute Gun Heo.

Similar presentations


Presentation on theme: "26 June 2012 Korea Rural Research Institute Gun Heo."— Presentation transcript:

1 26 June 2012 Korea Rural Research Institute Gun Heo

2 Piezometer Installation Introduction I I Conclusions V V Contents In-situ Experiments II Results and Discussion III IV - Borehole Image Processing System (BIPS) - In-Situ permeability test

3 Background & Purpose Seawater Blocking Securing fresh water Development Internal Purpose of Seadike The riprap-bottom layer connects both seaside and lakeside, so permeable Reclaimed with dredged sands Construction Condition of the Final Closing Section Piping and Erosion Embankment Desalination delay due to excessive infiltration were Concerned Evaluate the status of riprap layer Establish a long-term monitoring plan Evaluate the status of riprap layer Establish a long-term monitoring plan Determine whether need reinforcement Effective Safety management seadike Determine whether need reinforcement Effective Safety management seadike Dredged Sands Riprap Bottom Layer

4 Outline To evaluate the Filling Status Filling Status To evaluate the Permeation Permeation To measure the Pore Pressure Installation Piezometer Items Borehole Image Processing System (BIPS) In-situ Permeability test Installation Piezometers and Building Monitoring System (Automated) Visually check the Filling Status of the Bottom Layer. Comparison the degree of permeability (General / Final closing) Long-term Monitoring ⇒ Evaluate the temporal variation of Filling Status ⇒ Propose Criteria for Monitoring Purpose Detailed Task Utilization Determine whether need reinforcement Safety Management Determine whether need reinforcement Safety Management Field test results + Data measured Evaluated Current state of the filling & temporal variation of Filling Status Proposed Criteria for Monitoring

5 Bottom Protection Layer of the Final Closing Section To find the most vulnerable sections…

6 Electrical Resistivity Results electrical resistivity results of No ~No (5m electrode gap) Below Above No Relatively low resistivity and showing the continuity sections

7 Selected Sections(3 Final Closing Sections, 1 General Section) No No No No

8 BIPS (Borehole Image Processing System) BIPS To decipher the filling degree of the bottom layer No of Halls LocationFocused 4 Near the Piezometer Riprap Bottom Layer Top (13.9m) Dredged Sands Riprap Dredged Sands Bottom (17.1m) Results

9 In-situ Permeability test Permeability Test Results To compare the differences in permeability coefficients NumberLocationTest Section Permeability Coefficient k(cm/s) Remarks BH Embankment1.48×10 -3 Final Closing Section Bottom Layer3.25×10 -3 BH Embankment2.38×10 -3 Bottom Layer2.29×10 -3 BH Embankment9.41×10 -4 Bottom Layer2.09×10 -3 BH Embankment1.25×10 -4 General Section Bottom Layer9.17×10 -4 The differences are not significant No of Halls LocationFocused 4 Near the Piezometer Riprap Bottom Layer Casing

10 Installation Piezometers 10 Piezometer Cross-Sectional I General Section 3 Final Sections Location Piezometer Items Automated measurement system has been built for four-sections By measuring the pore pressure, Compare those between general section and Final closing sections, evaluate the filling status of the bottom layer In addition, by conducting long-term monitoring, evaluate the safety of seadike with hydraulic head loss ratio Arranged piezometers to compare the pore pressure of each section (between the final closing section and normal section) Arranged piezometers to compare the pore pressure of each point (between P1 and P3, P3 and P7) 4 piezometers in bottom protection layer (P-1,3,5,7) 4 piezometers in embankment (P-2,4,6,8)

11 Monitoring Program 방조제평면도 상단메뉴 계측단면도 최근계측데이터 실시간표시 수두손실율그래프 간극수압그래프 경고표출범례 범례및계측요약 Floor plan Menu Bar Cross-section Hydraulic Head Loss Ratio Pore pressure Legend Measured Value

12 Measurement Results No.60+25(Final Closing section) P1 P3 P5 P7 Pore pressure changes due to tidal fluctuations that are quite stable From sea side to the lake side, the changes in pore pressure gradually decreases Time(day) Pore Pressure(kg/cm2) Time(day) Pore Pressure(kg/cm2) Time(day) Pore Pressure(kg/cm2) Time(day) Pore Pressure(kg/cm2)

13 Measurement Results No.65+00(Final Closing section) P1 P3 P5 P7 Pore pressure changes due to tidal fluctuations that are stable From the sea side to the lake side, the changes in pore pressure gradually decreases Time(day) Pore Pressure(kg/cm2) Time(day) Pore Pressure(kg/cm2) Time(day) Pore Pressure(kg/cm2) Time(day) Pore Pressure(kg/cm2)

14 Measurement Results No.69+80(Final Closing section) P1 P3 P5 P7 Pore pressure changes due to tidal fluctuations that are stable From the sea side to the lake side, the changes in pore pressure gradually decreases Time(day) Pore Pressure(kg/cm2) Time(day) Pore Pressure(kg/cm2) Time(day) Pore Pressure(kg/cm2) Time(day) Pore Pressure(kg/cm2)

15 Measurement Results No.82+00(General section) P1 P3 P5 P7 Pore pressure changes due to tidal fluctuations that are stable From the sea side to the lake side, the changes in pore pressure gradually decreases General section shows a smaller value than final closing section. Time(day) Pore Pressure(kg/cm2) Time(day) Pore Pressure(kg/cm2) Time(day) Pore Pressure(kg/cm2) Time(day) Pore Pressure(kg/cm2)

16 Building Monitoring System Installation Piezometer - 3 on the final closing sections(No.60+25, No.65+00, No.69+80) - 1 on the general section(No.82+00) - 8 Piezometers are installed on each section Monitoring Program - Express the results and Monitor for long-term Summary Every piezometer is operating properly Reliable pore pressure data are being collected Sea-side : Large Fluctuation, Lake-side : Small Fluctuation

17 Hydraulic Head Loss Ratio Tide/Pore pressure Head a : Hydraulic Head Loss Ratio ΔHp1,2 : changes of pore pressure head at P1, P2 “a” has the value of 0~1 when a=0, ΔHp1 = ΔHp2, a=1, ΔHp2 = 0 ← NOT affected by tide at all P1=tide level EL(m) P1-P2 EL(m) R 2 =Coefficient of determination The value of 0~1 Closer to 0, Unstable Closer to 1, stable Time (day) Tide (m) Pore pressure head (m) Overlapped two graphs. Gray : tide level Black : Pore pressure Head of somewhere inside the structure which is affected by tide but, depends on the position and the time, the ranges of pore pressure will be changed Hard to set a criteria Criteria(?) Sea-side inner-side embankment Hydraulic Head Loss Ratio

18 Changes of Trends Upward (Enlarged Head Difference) Downward (Lessened Head Difference) degree of dispersion (Change of the Infiltration Path) Changes of inclination

19 Evaluation by Hydraulic Head Loss Ratio (No.60+25) Bottom Protection Layer Embankment At P1, a = R 2 = 0.931, Blocking the water looks worse, but the behavior is stable At P7, a = R 2 = Closer to the Lake-side, values getting higher At P2, a = R 2 = 0.935, Blocking the water looks worse, but the behavior is stable At P8, a = R 2 = Closer to Lake-side, a value becomes higher a R2R2 a R2R2 With the Hydraulic Head Loss Ratio

20 Evaluation by Hydraulic Head Loss Ratio (No.65+00) Bottom Protection Layer Embankment At P1, a = R 2 = 0.950, Blocking the water looks worse, but the behavior is stable At P7, a = R 2 = Closer to Lake-side, a value becomes higher At P2, a = R 2 = 0.974, Blocking the water looks worse, but the behavior is stable At P8, a = R 2 = Closer to Lake-side, a value becomes higher a R2R2 a R2R2

21 Evaluation by Hydraulic Head Loss Ratio (No.69+80) Bottom Protection Layer Embankment At P1, a = R 2 = Closer to sea-side, Blocking the water looks worse, but the behavior is stable At P7, a = R 2 = Closer to Lake-side, a value becomes higher At P2, a = R 2 = Closer to sea-side, Blocking the water looks worse, but the behavior is stable At P8, a = R 2 = Closer to Lake-side, a value becomes higher a R2R2 a R2R2

22 Evaluation by Hydraulic Head Loss Ratio (No.82+00) Bottom Protection Layer Embankment At P1, a = R 2 = Closer to sea-side, Blocking the water looks worse, but the behavior is stable At P7, a = R 2 = Closer to Lake-side, a value becomes higher At P2, a = R 2 =0.993 Even though it closes to sea-side “a” value is relatively higher than the Final closing section’s At P8, a = R 2 = Closer to Lake-side, a value becomes higher a R2R2 a R2R2

23 Summary Location P1P3P5P7 aR2R2 aR2R2 aR2R2 aR2R2 No No No No Sea-side (P-1,3) : Blocking the water looks Bad, but the behavior is stable - Lake-side(P-5,7) : Blocking the water looks Good, and the behavior is stable - Blocking the water of the general section is Good, but the final closing sections also show a stable behavior - Reinforcement does not require now at the final closing section, however, need to monitor constantly

24 Criteria( Ⅰ ) Statistical Methods Three times the standard deviation were set to the criteria By setting the criteria, we could measure - Abnormal data - Upward mobility of trend lines - Downward mobility of trend lines - Changes of trend line inclination After long-term monitoring, we will - Review the adequacy of 3σ as criteria - Set the check-list in case of odd behavior Regression and 3-sigma Graph Tide(m) Criteria (-3σ) Criteria (+3σ) P1-P2 (m) Criteria suitable for long-term Monitoring

25 Examples of setting Criteria( Ⅰ ) No P1 P3 P5 P7

26 Criteria( Ⅱ ) Criteria based on the change of Hydraulic Head Loss Ratio

27 Criteria( Ⅱ ) By plotting the daily values, can predict changes of hydraulic head loss ratio Suitable for long-term monitoring Criteria based on the change of Hydraulic Head Loss Ratio Hydraulic Head Loss Ratio

28 Section Select 3 on the Final Closing Section (No , No , No ) 1 on the General Section (No ) In-situ Experiments BIPS : The gap was deemed to have been filled with the dredged sands In-situ permeability test : comparison of the permeability coefficient - Bottom protection layer / Embankment - General / Final Closing Section Difference is not large Conclusions

29 Building the Monitoring System Every piezometer is operating properly Evaluated the infiltration charcteristic by Hydraulic Head Loss Ratio - Sea-side (P-1,3) : Blocking the water looks Bad, but the behavior is stable - Lake-side(P-5,7) : Blocking the water looks Good, and the behavior is stable until now, evaluated need not reinforcement, but we will follow up the trend Suggested 2 Methods for Long-term Monitoring - Criteria Based on Statistical Method (Review the adequacy of 3σ by long-term monitoring) - Criteria based on the change of Hydraulic Head Loss Ratio (By the regression equation of trend line)

30 Applications Verify the stability of the sea-dike of the final closing section Monitoring technology for seawater intrusion were secured Methods for the structures affected by the tide were presented

31 Thank you very much!!


Download ppt "26 June 2012 Korea Rural Research Institute Gun Heo."

Similar presentations


Ads by Google