Geological Excursion at Ghyalchowk, Gorkha and Malekhu, Dhading

This geological field excursion was organized to provide the practical knowledge of geology to us about construction of tunnel, identification of mass failure or landslide and safety for geo-hazards.

Group Members: Prabin Sapkota (071BCE255) Pradeep Kumar Yadav (071BCE256) Pragyan Bhattarai (071BCE257) Prajwal Bhusal (071BCE258) Prakash Chandra Yadav (071BCE259) Pravin Aryal (071BCE260)

Submitted to: Department of Civil Engineering Thapathali Campus Kathmandu

Acknowledgement

The study of Engineering Geology remains incomplete without its practical knowledge. In real life we have to face a lot of practical problems that can’t be solved if we don’t have practical knowledge. For Civil engineering student the practical knowledge of the subject is essential.

The main work of a civil engineer is to study the feasibility of the construction and stability of structures in different types of land feature including rock, their slope, riverside and clayey portions. Literature alone cannot assist in producing any satisfactory results. Therefore, a thorough knowledge of actual field visit counts for its credit.

It is a matter of pleasure to have opportunity to field visit and field work in Engineering Geology. It helped us to build up confidence and have practical knowledge about the theories we studied in class.  This document contains the field studies that we have made in Malekhu and Gorkha and the corresponding theoretical backgrounds to understand it.

For the basic knowledge of field work of structural geology, the two days from 14th of Ashad to 15th of Ashad we were taken to Gorkha and Malekh for geological excursion. This performance was very effective for the partial fulfillment of knowledge and experience. However, the two days of tour was not sufficient to fulfill the requirement, we would like to express our gratitude to respected teacher Rijhu Shrestha who helped us during the field trip and taught many important things within the limited time period and for their kind support to make this tour informative. We would also like to thank the Department of Civil Engineering for providing us such an opportunity.

Methodology

The common methods used in the geological excursion were the site selection and the field observations. Different places suitable for the geological study were selected and their location was determined by the map and the observation related to such structures were taken and copied such as physical appearance, orientation, geological structures. Photographs were taken at many sites. In some, sketches were also plotted to assist the better understanding. In still some cases graphs were also plotted like in rock outcrop observation. And our teacher Rijhu Shrestha guided us and taught about different geological aspects like tunnel, landslide and rock mass classification.

OBJECTIVE

1. To study the Tunnel,
2. To study the mass movement by landslide and its geological terms,
3. To study the geological hazards and its remediation,
4. To classify the rock mass,
5. To realize the engineering significance of geological knowledge.

EQUIPMENTS REQUIRED

• Brunton Compass:

This compass is composed of delicate mirror and glass components which are vulnerable to shock and moisture thus, requiring care and periodic maintenance for proper application. Geologists use this as an instrument for measurement of the altitudes of structural features. This compass helps in the visualization of lines and planes in three-dimensional space.

• Geological Hammer:

A hammer was used to test the hardness of rock in the field and also to estimate approximate value of strength of intact rock material. It was performed by striking the tip of hammer and the surface of the rock whose hardness was to be determined.

• Measuring Tape:

A measuring tape was used to measure the distances between different discontinuities such as in the outcrop of rock strata. And it is used to locate the area one sq. metre for the rating of rock mass.


• Topo sheet:

A topo sheet is a shortened name for ‘Topographic sheet’. They essentially contain information about an area like roads, railways, settlements, canals, rivers, electric poles, post offices etc. According to their usage, they may be available at different scales (e.g. 1:25000, 1: 50000 etc., where the former is a larger scale as compared to the latter). They are made on a suitable projection for that area and contain latitude-longitude information at the corners. Thus any point on it can be identified with its corresponding latitude-longitude, depending upon the scale (i.e. if the scale is large, more accurate latitude-longitude).



• Goggles:

It is used for the safety of our eye from high intensity of the sun light and reflection of light on the field and also for preventing to reach in our eye the small fragments of the rocks while striking the rocks.

• Cap/hat:

Cap/hat is used to save the head from dust particles as well as direct encounter of sun light.

TOPOGRAPHIC INFORMATION:

• Very rugged, lesser Himalaya,
• Includes hills, river Valleys, river plain, escarpments, spurs, saddies, terrace, etc.
• Climatically subtropical zone.
• Altitude range: 300m – 2000m.

Introduction to Engineering Geology

Geology is the science which deals with about the origin, history and structure of the earth, as recorded in the rocks, together with the forces and possesses operating to modifying the rocks. Geology can be divided into two aspects:

1. Purely scientific research
2. Applied part – Engineering Geology.

Civil engineering planning, design, construction and monitoring, need geological knowledge. Knowledge of rock type and environment in which they form as well as their responses to weathering, erosion and the tectonic processes are useful in making estimating of site conditions and in formulating site investigation programs. After failure of the St. Francis Dam in California in 1928, the engineering profession gained the idea of careful design of structure with safety. After then, the engineering geologist appeared in the field of civil engineering. Engineer should be conscious for geological hazards such as active faults, landslides, rock fall, etc.  Rate of erosion, rock type, rate of weathering, etc. also influence in civil engineering work.
According to the IAEG, “Engineering Geology is the science devoted to the investigation, study and solution of engineering and environmental problems which may arise as the result of the interaction between geology and the works or activities of man as well as the prediction of and development of measures for the prevention or remediation of geological hazards”.

Objective of Engineering Geology:

• The main objective of engineering geology is to show the local geological conditions.
• Complex classification of rocks and history of the rock are of little professional values to an engineer.
• Geological data are vital for the identification of the projects, its feasibility (both economic and safety aspect), their design, proper construction and maintenance.
• Engineering projects are developed on the basis of economic, political, engineering and scientific consideration.
• Almost all of the civil engineering structures are placed on the earth’s materials (rocks and soils); so the judgment of the foundation materials in relation to their physical properties, engineering properties and orientation, falls within the scope of engineering geology.

Importance of Engineering Geology:

• For estimation of site location and condition.
• For evaluation of geological hazards.
• For selection and preparation of rock materials.
• For evaluation of cutting and drilling tools.
• For analysis of stress, stability and deformation of rock mass.
• For control blast procedure.
• For design of support system.

Excursion:

We had already gone to the geological excursion in 3^rd semester. At that time, we study about the features of geological structures as well as rock types and river channel morphology. We were familiar with dip direction, dip amount, strike, etc. But in this semester we have to study any one of the road/highway or tunnel projects under construction and geo-hazard problems in the field. This is according to our syllabus. So we have gone to the Malekhu for two days from 14th of Ashad to 15th of Ashad . We had stayed at Malekhu. Malekhu is situated at the Prithvi Highway, Dhading district, 70km south-west of Kathmandu valley. For the study of tunnel, we were taken to the tunnel constructed for Budhigandaki Hydropower Project for initial study. Tunnel is constructed for initial study of dam site of project. There are six tunnels. But we studied one tunnel at the road from Benighat, Dhading to Arughat, Gorkha. The tunnel is situated at 1.7 km North from Benighat, Dhading. Then at the second day, we were gone for the study of landslide (mass movement) and Rock mass classification near the Malekhu.
We study the field as scheduled:

S.N.	Date	Study of about	Discussion of	Location
1.	2073 Ashad 14	Tunnel	Tunnel related topics like tunnel construction, safety precautions, Support systems of tunnel, purpose of tunnel, etc.	Budhigandaki Hydropower Project Dam site Gorkha District, Ghyalchowk
2.	2073 Ashad 15	Landslide	Mass movement, land slide, different parts of landslide, cause of landslide, prevention of landslide,	About 500m towards Kathmandu from Malekhu, Dhading District at the Prithvi Highway.
3.	2073 Ashad 15	Rock mass Classification	The support system and condition of rocks by classifying the rock mass.	At 150m upstream of Malekhu river from bridge located on Prithvi Highway at Malekhu.

First of all, let us know about the theoretical knowledge:

Tunnel

Fig:Tunnel constructed for Budhigandaki hydropower Project

Tunnel is a civil engineering structure. A tunnel is an underground or underwater passageway, dug through the surrounding soil/earth/rock and enclosed except for entrance and exit, commonly at each end. A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers. Utility tunnels are used for routing steam, chilled water, electrical power or telecommunication cables, as well as connecting buildings for convenient passage of people and equipment.
A major tunnel project must start with a comprehensive investigation of ground/rock conditions by collecting samples from boreholes and by other geophysical techniques. Tunnels are dug in types of materials varying from soft clay to hard rock. The method of tunnel construction depends on such factors as the rock mass classification, the ground water conditions, the length and diameter of the tunnel drive, the depth of the tunnel, the logistics of supporting the tunnel excavation, the final use and shape of the tunnel and appropriate risk management.
The proposed tunnel’s location will determine what tools and techniques are necessary to construct it and prepare it for its intended use. Tunnels can be divided into 4 types:

• Soft-ground tunnels. These tunnels require support at the openings to keep the tunnel from collapsing. These tunnels are usually shallow and used for subways, water delivery, and wastewater removal systems.
• Rock tunnels. Because they are excavated from solid rock, these tunnels require little added support or none at all. Train and car tunnels are usually of this variety.
• Underwater tunnels. As the name indicates, these tunnels go under rivers, lakes, canals, and in the case of the “Chunnel,” straits such as the English Channel. These are the hardest tunnels to build, as water has to be kept away from the tunnel during and after construction.
• Building a tunnel under a city offers problems similar to an underwater tunnel, in that the ground around the tunnel tends to sag under the weight of the buildings above it. A knowledge of the area’s geology helps predict how much the ground will sag and suggests what methods can minimize the sagging.

Tunnel Construction:

For the construction of Tunnel following steps are followed/proceeded:

Procedure:

1. Geological Surveying/mapping: For the construction of tunnel, the geological surveying is done firstly to select the site. A geological survey is the systematic investigation of the geology/area to determine the character, relations, distribution, and origin or mode of formation of its rock masses and mineral resources beneath a given piece of ground for the purpose of creating a geological map or model. Numerous surveying techniques are used for geological surveys like laboratory test results, and modeling approaches to understand the characteristics of the earth. In the usual geological surveying, the primary information is concerning the study of rocks, their location, and the deformation and examination of the sedimentary layers. In addition, the soils, landscapes, rivers, and glaciers are examined. Generally surveying task includes:
   • Geological mapping
   • Structural mapping to indicate the location of the main rocks and the faults due to which they were placed there
   • Surficial mapping for the location of soils
   • Survey of topographic features
   • Formation of topographic maps
   • Survey to identify changes in landscapes, erosion patterns, and river channels
   • Subsurface mapping by seismic surveys, ground penetrating radar, and electrical tomography
2. Field Selection: After the geological surveying, the site for tunneling is selected. Selection of site is very important because it directly related to our project place and nearby village or city. We have to select the site which will be economic, effective and safe. Studies can initially be based on desk studies of the factors that decide the feasibility of the project. This goes for topics as topography, bathymetry, soil conditions/geology and nature.
3. Manual/Machining (TBM) Drilling: Drilling is a process of digging the earth surface making small whole for charging the explosion. The drilling can be done by means of machine or manual. TMB is used as an alternative to drilling and blasting (D&B) methods. TBMs are used to excavate tunnels with a circular cross section through a variety of subterranean matter; hard rock, sand or almost anything in between. As the TBM moves forward, the round cutter heads cut into the tunnel face and splits off large chunks of rock. The cutter head scarves a smooth round hole through the rock — the exact shape of a tunnel. Conveyor belts carry the rock shavings through the TBM and out the back of the machine to a dumpster.
4. Charging/keeping blasting material: For the construction of tunnel we have to muck the rocks from the site alignment. For this purpose, we can use blasting materials. This helps us to muck the rock pieces easily.
5. Blasting-mucking: The charged blasting material is exploded. Then the rock will be exploded into small particles. The process of removing of the exploded rock pieces form the tunnel is known as mucking. Hard rock tunneling and utilizes rock bolts and shotcrete applied immediately after blasting. This is often followed by a cast in-situ concrete lining using formwork.
6. Scaling ventilation: The process of removing remaining roof rocks which may be fall.
7. Support system: In the site of the tunnel construction, we have to determine that the rock property for the support system.
   • Steel Rib
   • Rock Bolting
   • Wire Mesh
   • Shotcrete

   Fig: Rock Bolting	Fig: showing steel rib
   Fig: Wire mesh	Fig: Shotcrete

Purpose of Tunnel:

Tunnel is constructed for the following purposes:

1. Tunnel is mainly used for drinking water supply, irrigation, transportation, hydropower production, mining, etc.
2. Tunnel makes route short and safe.
3. For the railway tunnel is very important.
4. Easy passage
5. Military purpose
6. For the study of intrusive rock types.
7. It connects two places in short distance which helps to reduce the transportation costs and saves the time.
8. For the initial study of any sites for different projects, the tunnel is constructed.

Our observation of Tunnel in Excursion:

Date: 2073 Ashad 14

Location and background:

We had gone Budhigandaki Hydropower Project site for the study of the tunnel which was constructed for the initial study of the dam site of the project, situated at Gorkha district 1.5 km north from the Benighat (on the Prithvi Highway), Dhading district. Budhigandaki is a national pride project. From here, government has decided to produce about 1200 MW electricity. For this purpose of project dam, the tunnel was constructed. There are six tunnels on both sides of Budhigandaki river, three of them are at Gorkha district and remaining three are at Dhading district.

Discussion:

We observed the tunnel. Our teacher guided the tunnel. They teach us about the construction process of the tunnel in short. If it was under construction, we can more easily understand the construction of the tunnel. But it was not under construction and the process of installing the support system. In tunnel, we can see firstly the support system. There is a steel rib support as shown in figure 9. We can easily observe the rock bolting at many places bolting the rock strata. There is also short crete system near steel rib support. Wire mesh is also introduced in the tunnel. Ongoing in, we feel cold than surrounding outside. After finishing, we take our group pictures at tunnel.

Mass Movement

The force of gravity acts to tear the mountains down causing a variety of phenomena collectively called mass wasting or mass movements, where by geological materials are move downward from one place to another. Movement can be sudden, swift and devastating, as in rockslide or avalanche. Mass movement refers to all types of movements either slowly or quickly and with or without plane failure. But in landslide, there should be plane failure.

A. Landslide:

Generally, it is fast falling of soil along with rocks, water and vegetation due to failure of plane of land. Downward and outward movements of slope forming minerals along surfaces of separation by falling, sliding and flowing at a faster rate, is called as land slide. Especially, land slide occurs at mountain region, tunnels, etc. but it can happen or occur in low relief area.  The influence of gravity is constant operation for landslide. Landslide has the great power for destruction of civil engineering construction. So it comes under the study of our course.

Landslide Anatomy:

fig: Anatomy of the landslide

1. Crown: It is the top portion of the landslide.
2. Main scrap: It is steep surface at upper part of the landslide from which the surface starts to fall/slide.
3. Minor scrap: It is also steep surface at displaced mass.
4. Head of landslide: Upper portion of displaced mass.
5. Main body: Part of displaced material that overlies surface of rupture between scarp and toe of surface of rupture.
6. Foot: The line of intersection of the lower part of the slip plane and the original ground surface.
7. Tip: The farthest point from the top of the landslide.
8. Toe: The lower portion, usually curved margin of the displaced mass.
9. Surface of rupture: Surface that forms lower boundary of displaced material below original ground surface.
10. Zone of depletion: Area of landslide within which displaced material lies below original ground surface.
11. Zone of accumulation: The area of landslide within displaced material lies above the original ground surface.
12. Flanks: Sides of slides i.e. left flank or right flank.
13. Traverse cracks: The vertical cracks are traverse cracks.
14. Longitudinal cracks: The horizontal cracks are longitudinal cracks.
15. Height: It is the vertical distance from crown to toe.
16. Depth: It is the thickness of the slide mass between crown and foot.

Classification of landslide (Varnes, 1978):

Type of movement		Type of material
		Rock	Engineering Soil
		Bedrock	Debris	Earth
Falls		Rock Fall	Debris Fall	Earth Fall
Topples		Rock Topple	Debris Topple	Earth Topple
Slides	Rotational slide (few units)	X	Debris Slump	Earth Slump
	Translational slide (many units)	Rock block slide Rock slide	Debris block slide Debris slide	Earth block slide Earth slide
Spreads		Rock Spread	Debris Spread	Earth spread
Flows		Rock Flow (Deep Creep)	Debris Flow	Earth Flow
Complex		Combination of two or more types of movement

Different types of landslide and mass movement:

1. Falls:
   Falls are abrupt movements of masses of geologic materials, such as rocks and boulders, that become detached from steep slopes or cliffs. Separation occurs along discontinuities such as fractures, joints, and bedding planes, and movement occurs by free-fall, bouncing, and rolling. Falls are strongly influenced by gravity, mechanical weathering, and the presence of interstitial water. Depending on the type of materials involved, the result is a rock fall, soil fall, debris fall, earth fall, boulder fall and so on.
2. Topples:
   Toppling failures are distinguished by the forward rotation of a unit or units about some pivotal point, below or low in the unit, under the actions of gravity and forces exerted by adjacent units or by fluids in cracks. The condition of for toppling is defined by the position of weight vector in relation to the base of the block. If the centre of gravity occurs outside the base of the rock or mass, then toppling occurs.
3. Slides:
   Although many types of mass movements are included in the general term “landslide,” the more restrictiveuse of the term refers only to mass movements, where there is a distinct zone of weakness that separates the slide material from more stable underlying material. The two major types of slides are rotational slides and translational slides.
   1. Rotational slides:
      This is a slide in which the surface of rupture is curved concavely upward and the slide movement is roughly rotational about an axis that is parallel to the ground surface and transverse across the slide. Rotational slides occur on slopes of homogeneous clay or shale and soil slopes. A slump is an example of rotational slide. Successive rotational slide occur until the slope is stabilized.

   

   2. Translational slides:
      It occurs in inclined stratified deposits, the movement occurring along the planar surface, frequently a bedding plane with little rotation or backward tilting. The translational slide is controlled by surface of weakness such as bedding planes, joints and faults. The translational slides in which the slip surface is roughly parallel to the ground surface, are called as slab slide.
4. Spreads:
   Failure in this case is cause d due to liquefaction. The dominant mode of movement is lateral extension accompanied by shear or tensile fractures. The failure is caused by liquefaction, the process whereby saturated, loose, cohesionless sediments (usually sands and silts) are transformed from a solid into a liquefied state. Failure is usually triggered by rapid ground motion, such as that experienced during an earthquake, but can also be artificially induced.
5. Flows:
   In a flow the movement resembles that of viscous fluid. Slip surfaces are usually not visible. The movement requires the present of water. Different types of flow are described below:
   1. Debris flow:
      A debris flow is a form of rapid mass movement in which a combination of loose soil, rock, organic matter, air, and water mobilize as a slurry that flows downslope. Debris flows include less than 50% fines. Debris flows are commonly caused by intense surface-water flow, due to heavy precipitation or rapid snowmelt, that erodes and mobilizes loose soil or rock on steep slopes. Debris flows also commonly mobilize from other types of landslides that occur on steep slopes, are nearly saturated, and consist of a large proportion of silt- and sand-sized material. Debris-flow source areas are often associated with steep gullies, and debris-flow deposits are usually indicated by the presence of debris fans at the mouths of gullies. Fires that denude slopes of vegetation intensify the susceptibility of slopes to debris flows.
   2. Earth flow:
      Earthflows have a characteristic “hourglass” shape. The slope material liquefies and runs out, forming a bowl or depression at the head. The flow itself is elongate and usually occurs in fine-grained materials or clay-bearing rocks on moderate slopes and under saturated conditions. However, dry flows of granular material are also possible.
   3. Mud flow:
      A mudflow is an earthflow consisting of material that is wet enough to flow rapidly and that contains at least 50 percent sand-, silt-, and clay-sized particles. In some instances, for example in many newspaper reports, mudflows and debris flows are commonly referred to as “mudslides.”
6. Creep:
   Creep is the imperceptibly slow, steady, downward movement of slope-forming soil or rock. Movement is caused by shear stress sufficient to produce permanent deformation, but too small to produce shear failure. There are generally three types of creep:
   1. seasonal, (due to changes in soil property moisture and soil temperature);
   2. continuous, (shear stress exceeds continuously the strength of the material); and
   3. progressive, (slopes reaches the point of failure).

   Creep is indicated by curved tree trunks, bent fences or retaining walls, tilted poles or fences, and small soil ripples or ridges.

Causes of landslide:

Geological causes:

1. Extensive development of weak rocks
2. Weathering of rock mass
3. Sheared materials
4. Adversely oriented structural discontinuity as bedding, joints, foliation, cleavage, schistosity and faults.
5. Seismic activity

Morphological causes:

1. High relief or Steep slopes
2. Undercutting (toe cutting) of banks by deeply incised rivers and streams.
3. Tectonic upliftment or subsidence.

Physical causes:

1. Intense rainfall (Role of water)
2. Rapid snow melt or Glacier Lake Outburst Flood (GLOF) activation.
3. Volcanic eruption, etc.

Human (Anthropogenic) causes:

1. Deforestation
2. Improper land use
3. Construction activities
4. Water leakage

Preventive Measures for Landslides:

The preventive measures are based on

1. Possible Damage on Human life
2. Damage on public Structures like Buildings, roads, canals, bridges, hydropower, etc.
3. River flooding due to river damming.

Methods of Prevention:

1. Drainage management and damming of river.
2. Use of retaining Structures
3. Slope Reinforcement by rock Bolting
4. Slope Treatment
5. Afforestation
6. Bioengineering (Bio technical) stabilization
7. Excavation and filling, etc.

Effects of Landslides:

• Destruction of settlement areas like, village, town.
• Destruction of man-made constructions, infrastructures like bridges, dams, canals, schools, hospitals, industries, roads, railways, etc.
• Chance of blocking the river which may be cause of more destruction of wealth-peoples.
• Disperse of minerals
• Cracks may develop
• Cause deforestation
• Fertile soil moves down leaving the land unfertile.
• Cause siltation problems in reservoirs.
• Upsets both land and marine ecosystem.

B. Slope failure/ rock slide:

Generally, it occurs on steep slopes controlled by the discontinuity patterns with in the parent rock. It is composed of boulders. And Water is seldom factor in causing rock slides, although it may weaken bonding along joints and bedding planes. Freeze- thaw action, however, is an important cause. Relatively small dimension movements of weathered rock or soil layer in the slopes are called as slope failures could lead to more stable configuration may redistribute the rock material in less steep slopes and it relief the stress by reducing the high concentration of stress usually present at the valley bottoms.

C. Debris flow:

Debris slides are usually restricted to the weathered zone or to surficial talus. Debris flow is a form of rapid mass movement in which loose soils, rocks and organic matter combines with entrained air and water to form slurry that then flows may down-slope. The mass movement associated with steep gullies.

Our Observation of Landslide in Excursion:

Date of Survey:	2073/Ashad/15
Location of landslide:	About 500m towards Kathmandu from Malekhu, Dhading District at the Prithvi Highway.
Side Road:	left from Kathmandu to Narayanghat on Prithvi highway
Field Supervisor:	Group-of-roll-no-071/BCE/255 to 071/BCE/260
Area:	Hill/ River Valley

Description
1.	Geometry
	Extent
	Width of Slope Toe:			About 50		meter
	Depth (Approx):			About 1		meter
	Length of Slope:			About 10		meter
	Slope Angle of Range:			About 60-70		degree
	Average Angle of Slope:			About 65		degree
2.	Geological Characteristics:
	Composition of Landslide masses
	Aluvium	✔️	Colluvium		Lake Deposites				Others
	Characteristics of Gravel/Sand/Slit/Clay/Peat/others:
	Small Pieces of bedrock, size varies from small to boulders, Silt stone, quartzite, dolomite, etc. rocks.
	Soil Type:
	According to Unified Soil Classification (USC):
	Soil Sample:
	Sample Numbers:
	1.		2.		3.		4.		5.
	Insitu Test (if any):
	Soft Rock (Silt Stone/Phyllite/Slate/Clay Stone/Schist/Others):										✔️
	Hard Rock (Quartzite/Granite/Gneiss/Limestone/Sandstone/Dolomite/Others):										✔️
	Tone Colour:		Graywhite
	Weathering Condition:			High-H			Moderate-M		M	Low-L
	Others-Rock characteristics and Structure: Silt, Quartzite, Dolomite/ limestone, etc types of rocks are present in the rock fall
	Sample (with location):			1.			2.			3.
	Insitu Test (if any):
	Other Remarks (Attitude):			Sub-tropical Region
3.	Geomorphological Characteristics:
	Scarp:		Yes		No
	Existing If “Yes” (Y), “No” (N)				Length	about 10m		Width	1m
	Gradient:		vertical
	Tension Crack:		Yes		No
	If “Yes” (Y), “No” (N)				Length	……..		Width	…..	No.:	……
	Gully: If “Yes” (Y), “No” (N)				Yes		No
4.	Hydrological Information
	a.	Ground Water Condition:
		Dry		Wet		Flowing			Discharge
	b.	Number of Gullies:
		No		Few		Many
	c.	Surface Water Runoff:
		Yes		No
	d.	Type/condition of existing drainage:					Road drainage is present
	e.	Remarks (Rain Fall Patterns):

Rock-mass Classification:

Rock mass classification systems are used for various engineering design and stability analysis. According to engineering uses, rocks are classified into intact rock and rock mass.
The intact rock is the rock, free of joints. If joints are present, the rock is rock mass. Rock mass classification systems are developed as to obtain quantitative value from rock. Useful index tests are used to evaluate the suitability of rock for making infrastructures.
Rock-mass is classified based different universal parameter.

Rock Mass Rating (RMR):

The Rock Mass Rating (RMR) System is a geo-mechanical classification system for rocks, developed by Z. T. Bieniawski between 1972 and 1973. Bieniawski’s Geo-mechanics classification system provides a general rock mass rating (RMR) increasing with rock quality from 0 to 100. It is based upon following five universal parameters.

1. Uniaxial compressive strength of rock material
2. Rock quality designation (RQD)
3. Spacing of discontinuities
4. Condition of discontinuities
5. Groundwater conditions
6. Orientation of discontinuities

The numerical values are given for all the parameters. According to Bieniawski (1993), the objectives of rock mass characterization and classification are:

• to identify the most significant parameters influencing the behavior of a rock mass;
• to divide a particular rock mass formation into a number of rock mass classes of varying quality;
• to provide a basis for understanding the characteristics of each rock mass class;
• to derive quantitative data for engineering design;
• to recommend support guidelines for tunnels and mines;
• to provide a common basis for communication between engineers and geologists;
• to relate the experience on rock conditions at one site to the conditions encountered and experience gained at other.

Conclusion:

This geological field excursion to Gorkha and Malekhu was organized to provide the practical knowledge of geology to us. The geological excursion is aimed to provide the acquaintance and knowledge of geological element and their properties as well as features. Our tour was very interesting, informative, subjective and practical with engineering scope of our future carrier. This excursion was organized according to our syllabus and we are thankful to our Civil Engineering Department and teachers, Thapathali Campus.

Referece:

• “Geology for Civil Engineers” by Kabiraj Paudyal, Oxford International Publication.
• Stratigraphy of lesser Himalaya, Malekhu area by Stocklin and Bhattarai (1977) and Stocklin (1980)
• Blogspots
• Google
• Wikipedia
• http://www.brighthubengineering.com/geotechnical-engineering/61113-geological-surveying-and-mapping/
• http://geology.com/usgs/landslides/
• https://tu-freiberg.de/
• https://pravinaryal.blogspot.com