सुरुङ निर्माणमा नियन्त्रित विस्फोटन: प्रविधि र विस्फोटकको छनोट
नेपालमा जलविधुतीय, सडक सुरुङ, तथा खानेपानी आयोजनाजस्ता पूर्वाधारहरूको तीव्र विकाससँगै सुरुङ निर्माण परियोजना उल्लेखनीय वृद्धि भएको छ।
हिमाली भूभाग र जटिल भूगर्भीय बनावटका कारण, यस्ता परियोजनाहरूमा नियन्त्रित विस्फोटन (Control Blasting) एउटा सुरक्षित र प्रभावकारी खनन विधिका रूपमा प्रयोगमा आएको छ। यसको मुख्य उद्देश्य भनेको संरचनात्मक स्थिरता कायम राख्दै, वातावरणीय क्षति न्यूनीकरण गर्नु र कामदार तथा वरपरका समुदायको सुरक्षा सुनिश्चित गर्नु हो। यसैले, नेपालको जटिल भूपरिवेशमा नियन्त्रण गरिएको विस्फोटन केवल प्राविधिक उपाय मात्र नभई एक रणनीतिक विकल्प पनि बनेको छ।
नेपालमा नियन्त्रित विस्फोटनको कार्यविधि
नियन्त्रित विस्फोटन प्रक्रिया प्रारम्भमा विस्तृत भूगर्भीय र प्राविधिक अध्ययनबाट सुरु हुन्छ। नेपालको भौगोलिक विविधताका कारण ग्रेनाइट, चुनढुङ्गा, र अन्य नरम चट्टानहरू विभिन्न स्थानमा पाइन्छन्, जसअनुसार विस्फोटन डिजाइन (Design) फरक हुन्छ।
इन्जिनियरहरूको सहायताले विशेष ढाँचामा ड्रिलिङ होलहरू खनिन्छन् जस्तै:
- कट होलहरू: सुरुङको केन्द्र भागमा प्रारम्भिक विस्फोटनका लागि।
- लिफ्टर होलहरू: भुइँ चट्टान निकाल्नका लागि तल्लो भागमा।
- पेरिमीटर होलहरू: सुरुङको सटीक रूप र सीमाना निर्धारण गर्न।
यी प्वालहरूको स्थान, कोण र गहिराइ चट्टानको किसिम अनुसार तय गरिन्छ ताकि अव्यवस्थित रूपमा विस्फोटन कम होस् र सुरुङको आकार सटीक रहोस्।
प्रमुख नियन्त्रित विस्फोटन प्रविधिहरू
- स्मूथ विस्फोटन – भित्ताहरूलाई समतल र स्थिरराखी हल्का विस्फोटकसहित नजिकै ड्रिल गरिन्छ।
- पूर्व विभाजन – मुख्य विस्फोटन भन्दा अघि चिरा पारेर अव्यवस्थित रूप न्यूनीकरण गरिन्छ।
- कुशन विस्फोटन – मुख्यतया सुरुङको छेउ भागमा प्रयोग हुने प्रविधि जसले भित्ताहरू सुरक्षित राख्छ।
- डिले विस्फोटन – प्वालहरू क्रमशः मिलिसेकेन्डको फरकमा विस्फोट गरिन्छ, जसले कम्पन र क्षति घटाउँछ।
विस्फोटक छनोट
विस्फोटक सामग्रीको छनोट चट्टानको प्रकृतिमा आधारित हुन्छ
- कठोर चट्टानहरू जस्तै ग्रेनाइट, दर्शनढुङ्गा– उच्च शक्तिका विस्फोटक जस्तै इमल्सन
Emulsion) वा एएनएफओ (ANFO – Ammonium Nitrate Fuel Oil) प्रयोग गरिन्छ । यी विस्फोटकहरूको डिटोनेसन वेग (Detonation Velocity) र उर्जात्मक क्षमता उच्च हुन्छ । - मध्यम कठोर चट्टानहरू जस्तै चुनढुङ्गा – मध्यम श्रेणीका विस्फोटकहरू उपयुक्त हुन्छन्।
- नरम चट्टानहरू – जस्तै सिल्टस्टोन कम ऊर्जा दिने विस्फोटक प्रयोग गरिन्छ ताकि अनावश्यक क्षति नहोस्।
आधुनिक प्रविधिको प्रयोग: इलेक्ट्रोनिक डिटोनेटर
हालका वर्षहरूमा सुरुङ निर्माणमा नन–इलेक्ट्रिक (NONEL) वा इलेक्ट्रिक क्याप (Electric Caps) को तुलनामा, इलेक्ट्रोनिक डेटोनेटरहरूले (Electronic Detonators – EDs) मिलिसेकेन्ड स्तरमा उच्च सटीकता प्रदान गर्छन्, जसले विस्फोट नियन्त्रण, सुरक्षा, र परिणाममा उल्लेखनीय सुधार ल्याएको छ।
यस प्रविधिका विशेषताहरू:
- विस्फोट समयको अत्यन्त उच्च सटीकता (मिलिसेकेन्डको अन्तरमा विस्फोट)
- विस्फोटनको राम्रो नियन्त्रण
- कम कम्पन
- संरचनात्मक जोखिममा उल्लेखनीय कमी
- अधिक सुरक्षित कार्य वातावरण
नेपालजस्तो जटिल भूगर्भीय संरचना भएको मुलुकमा, यो प्रविधि प्रभावकारी मात्र नभई अत्यावश्यक बनिसकेको छ।
the people living. Tunneling in Nepal started in 1917 with the first tunneling project the Churia Tunnel which is a highway tunnel of 500 meters long that facilitate trade between Kathmandu and Raxaul. The use of underground space is not new and people in this country have used underground space for many years, with early miners digging small tunnels and caves to get minerals like copper, iron, lead, cobalt, nickel, and different colored stones. In recent past the tunneling activities have increased considerably in the country with the development of many medium scale hydropower projects. 
the excavation of tunnels and an underground powerhouse for the Tinau Hydroelectric Project near Butwal in 1970, marking the beginning of approximately 75 kilometers of tunnel construction. Numerous hydropower development projects have been implemented till date, along with the country’s first road tunnel construction project, the Nagdhunga Tunnel which is now nearing completion. In Nepal, major rivers originate in the Himalayas and hold substantial potential for hydropower generation. Moreover, the future of tunneling in Nepal looks promising with several ongoing and planned projects mostly related with transportation and Hydropower. These projects are indicating the growth in Nepal’s infrastructure development.
As of 2025, Nepal employs various types of explosives in it’s tunneling projects, particularly for hydropower and infrastructure development. The selection of explosives materials such as detonators, initiating system, packed explosives and others is influenced by geological conditions, project scale, and availability. Challenges are still yet to be overcome in complex geological structures in Nepal. To mitigate this limitation of traditional method, Nepal is gradually adopting Tunnel Boring Machine (TBM) for tunnel excavation. TBM can be the most efficient method of tunneling as Nepal has a critical structure, TBM can help in completion of projects in less period with safety and less environment impact. 
particularly for hydropower, road tunnels, and water supply systems. Given the country’s mountainous terrain and complex geology, controlled blasting has become a critical method for safe and efficient tunnel excavation. In various underground projects, blasting must be carried out with precision to ensure structural stability, protect surrounding environments, and minimize risk to workers and nearby communities. Therefore, controlled blasting, is not only a technical necessity but also a strategic choice in Nepal’s challenging tunneling environment.
These devices represent a major improvement over traditional initiation systems such as non-electric (NONEL) or electric caps, providing millisecond-level precision, improved safety, and enhanced control over blast outcomes. The accuracy that electronic detonators provide is extremely beneficial for Nepal’s complicated geology. The use of modern blasting techniques support systems is crucial for maintaining tunnel stability during and after excavation.
(28.1 Mw) is runoff river type project located at Ramechhap and Okhaldhunga Districts. The total length of the tunnel is 4797 m, and the excavation of tunnel is done by traditional drilling and blasting process. MMSM helped overcome the challenges by supplying the necessary explosive technologies.
The tunnel has a height of 8.3 meters and a lane width of 9.5 meters. Therefore, the Nagdhunga Tunnel Project is a game-changer for Nepal’s road infrastructure, aiming to reduce travel time, ease traffic congestion, and improve connectivity between Kathmandu and the western regions of Nepal.
Thus, this led to safe and controlled blasting to break through tough rock formation, timely excavation, and minimized environmental impacts.
Naghdhunga Tunneling Project is now in its final stage, with approximately 87 percent of the construction work completed. Even with the rapid progress of construction, it will take a year before the tunnel route is ready for vehicle operation. Once the project is completed it will take seven minutes to travel from Sisnekhola to Balambu. Additionally, the flyover towards Balambu is in its final stage, with about 97 percent of the work already completed. Thus, by the end of 2025, the tunnel is expected to be softly opened.
