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Geophysical survey of Huai Phai - Lum Pa Yang. diversion tunnel project, KALASIN. Noppadol Poomvises Geologist 6 (handsome, smile & single). Objectives of the project. To diverge excessive water from Huai Phai reservoir to Lum Pha Yang irrigation area.
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Geophysical survey of Huai Phai - Lum Pa Yang diversion tunnel project, KALASIN Noppadol Poomvises Geologist 6 (handsome, smile & single)
Objectives of the project • To diverge excessive water from Huai Phai reservoir to Lum Pha Yang irrigation area. • To supply the water to an area of the new theory agricultural system (under H.M. the King) at Kao Wong district, KALASIN province.
Four alternatives of the diversion method • Open trench • Surface pumping • Siphon • Subsurface tunneling
Solution Conditions • Subsurface tunneling • App. 1,000 m long • Inlet at app. +290.000 m msl. • Outlet at app. +210.000 m msl. • Safe • Economics • Effectiveness • Unaffected to a forest area class 1A.
Survey area Tunnel route 1 km Modified from Royal Thai Survey Department,1973 Lum Pa Yang, KALASIN Huai Phai MUKDAHAN 10 km Modified from Department of Highways , 1999 Modified from Patton & Hendron, 1972 Kingdom of Thailand Figure 1 Location, topography, idealized geological structure, and proposed survey area of The Huai Phai - Lum Pa Yang diversion tunnel project. Survey area
Lum Pa Yang, KALASIN Huai Phai MUKDAHAN Tunnel route Modified from Patton & Hendron, 1972 1 km Modified from Royal Thai Survey Department,1973 Topography Assumed earth model
Proposes of the surveys To determine depth of bedrock. To evaluate a stability condition of foundation rocks. To detect a subsurface structure. To point out anomalous bodies hidden. Three main methods used Seismic refraction survey. Seismic reflection survey. VES survey using Schlumberger array. Geophysical surveys
A' Top view LPYR LPYC B Assumed talus deposit LPYL 100 m D A Location of sounding C' C Refraction survey lines B' D' Reflection survey lines Huai Phai reservior area Side view Lum Pa Yang agricultural area Figure 2 Geophysical survey lines and sounding location. Seismic survey lines and VES locations
Shotpoint positions (a) Data acquisition (b) Data processing using reciprocal time method and Hakiwara's graphic technique (c) Seismic refraction profile Concept of refraction survey
r p D C (a) Basic principle R (Sharma, 1997, p.211) (b) Data acquisition (Milsom, 1996, p.75) (c) Data processing using curve matching method r r W r (Sharma, 1997, p.230) r r r (d) Presentation of VES result Concept of VESusing Schlumberger array
Seismic refraction profile along center line (A-A') of tunnel Looking Northwest Scale 1 : 500 , H : V = 1 : 1 Seismic refraction profile lpy-1 lpy-1 along cross line (B-B') lpy-1 lpy-1 lpy-1 Looking Northeast lpy- lpy-09 lpy-08 lpy-1 lpy-07 lpy-06 lpy-05 Scale 1 : 500 , H : V = 1 : 1 lpy-04 lpy-1 lpy-0 lpy-02 lpy-01 lpy-1 02 lpy-1 01 0 3 2 400 กรมชลประทาน ผลสำรวจคลื่นไหวสะเทือนหักเห ตามแนวอุโมงค์ โครงการอุโมงค์ผันน้ำลำพะยังตอนบน (อันเนื่องมาจากพระราชดำริ) ต.สงเปลือย อ.เขาวง จ.กาฬสินธุ์ งานตรวจสอบธรณีเทคนิค 2 สำรวจ ประมวลผลและแปลความหมายโดย 1. นายนพดล ภูมิวิเศษ นักธรณีวิทยา 6 ฝ่ายตรวจสอบธรณีเทคนิค 2. นายสัญชัย พงสาวัฒนา นักธรณีวิทยา 6 ส่วนวิทยาการธรณี 3. นายนพดล สินธุบุญ นักธรณีวิทยา 3 สำนักสำรวจด้านวิศวกรรมและธรณีวิทยา กวธ. ฝ.7 0360 Figure 3 Seismic refraction profile along diversion tunnel route Seismic refraction profile along tunnel route
lpy-1 lpy-1 lpy-1 lpy-1 lpy-1 lpy- lpy-09 lpy-08 lpy-1 lpy-07 lpy-06 lpy-05 lpy-04 lpy-1 lpy-0 lpy-02 lpy-01 lpy-1 02 lpy-1 01 3 0 2 400 กรมชลประทาน ผลสำรวจโดยวิธีวัดค่าความเร็วคลื่นไหวสะเทือนหักเห และวัดค่าความต้านทานไฟฟ้า บริเวณหินหล่นเชิงผา ปากอุโมงค์ผันน้ำ โครงการอุโมงค์ผันน้ำห้วยไผ่-ลำพะยังตอนบน ต.สงเปลือย อ.เขาวง จ.กาฬสินธ์ Figure 4 Result of seismic refraction and resistivity sounding along an assumed talus body นพดล ภูมิวิเศษ 9 สิงหาคม 2542 ประมวลผลและแปลความหมาย Seismic refraction profile and VES along talus body
Results • Seismic refraction • 330 - 630 m/s (topsoil), • 900 - 2,000 m/s (weathered rock and talus deposit), • 3,100 - 4,400 m/s (strong bedrock). • 7 LVZs at tunnel routeand4 LVZs at talus body interpreted as fracture zones. • Proven small, narrow, and thin in shape of talus body. • Seismic reflection • Gentle-dipping earth layers, with 2 sets of discontinuity as open fractures, and some local faults. • VES by Schlumberger array • 23 - 181 Ohm.meter (top soil). • 6.8 - 71 Ohm.meter (weathered rock). • 32 - 955.9 Ohm.meter (bedrock). • Depth of bedrock from VES is well conformable with refraction results, but shallower only if acquiring nearly about LVZs.
Conclusions • Depth of bedrock < 15 m. • Rippable overburden along survey lines ~ 3 - 15 m. • Stability condition of foundation rock is fair, but supporting and treatment are required. • Proven thick sedimentary sequence with gentle dipping monocline structure. • Anomalous bodies hidden • Shallow parts, 7 LVZs along tunnel route and 4 LVZs along talus body. • Deeper, 2 sets of discontinuity widely existed along tunnel, and steeply dipping to NE and SW.
Figure 6 Three alternatives of the Huai Phai - Lum Pa Yang diversion tunnel (modified from Kamart, 2000) Three alternatives of diversion tunnel
