The distance between the two tracks on any railway route is known as railway gauge. The wooden or concrete supports for the rail tracks are known as a sleeper as British English or cross tie as American English.
Railway Gauge
Sleepers:
A sleeper is a rectangular support for the rail tracks. It is laid perpendicular to the rail sleepers and transfer loads to the track ballast and subgrade.
Sleepers hold the rails upright and keep them spaced to the correct gauge.
Sleeper
Railway Fastening System
Ballast:
Ballast is the name for the stones beneath the track. It forms the track bed upon which railroad sleepers are laid and is used to bear the load from the railroad ties to facilitate drainage of water and also to keep down vegetation that might interfere with the track structure.
Railway Ballast
The ballast also holds the track in place as trains roll over it and absorb the noise. It typically consists of a crushed stone rail fastening system. It is referred to as a group of railway fasteners that are used to fasten steel rail to railway sleeper.
Fish Plate:
Fish plate is used to join two different rail tracks without welding leaving some gaps at the joining of the track so that when they get heated it doesn’t bend. There are foor bolts that hold up the tracks together.
Fish Plate
Rail Track GAP
There is another type of fish plate called juggled fish plate. This is a specially designed fish plate with convexity in the center to accommodate weld collar at newly welded joints to protect defective welded joints and to carry out emergency repair of weld failures.
Bridges are marvels of engineering that stand inconspicuously amongst us. We don’t think of them much even when we are passing over them. Nowhere are these structures more impressive then when the are built over water, which brings us to the question how are bridges built over water?
When the water is shallow, construction is easy. A temporary foundation is made on which piers are built to support the upper structure and the bridge is then built! It’s when the water is deep that other techniques are needed.
There are many methods to complete such as task in deep water but here we will explore the main three. These three methods of bridge building are called battered piles, cofferdams and caissons.
Battered Piles:
These are poles that are driven into the soil underneath the water. Piles are hammered into the water until the turn outward or inward at an angle. This makes the piles firm and increases their ability to carry lateral loads.
Piles are inserted in the ground using pile drivers. These are mechanical devices that may be transported to a location on a floating pile driving plant.
Battered Piles at a bridge project in Sweden
Pile drivers may also be cantilevered out over the water from piles that have been installed in advance. With the use of pile frames, pile hammers and winches, pile drivers hammer the piles into the soil until the turn outward or inward at an angle. The pile are now ready to carry lateral loads and can provide the foundation of support for the bridge.
The next step is to construct the pile caps above the piles. Once this is done, the bridge is ready to be built.
Cofferdams:
These are temporary enclosures made be driving sheet piling into the bed of a body of water to form a watertight fence. This is called the cofferdam. There is more to this bridge technique. Once the sheet piles have been inserted in the water to create a cofferdam, the water is pumped out of the enclosure.
Now, the construction workers can built the bridge as if the are working on dry land. The process then becomes relatively easy.
Cofferdam
Caissons:
There are two types of caissons, open and pneumatic.
An open caisson is a structure that is usually shaped like a box. It is open, at the top and bottom. The caisson is usually constructed on land then floated into position and sunk, so that the upper edge is above water level.
The caisson has a cutting bottom edge so that it sinks through soft silt on the bed. Inside is a series of large pipes or dredging wells. These are used to dredge up the bed material. As more material is dredged up, the caisson sinks and more sections are added to the shaft to keep it above water.
Once the caisson reaches the correct depth, concrete is laid to seal the bottom and then more concrete is poured into the caisson to form a solid post.
Steel Open Caisson
A pneumatic caisson is similar to an open caisson but it has an airtight bulkhead above the bottom edge. This is fitted with air locks. The space between the cutting edge and the bulkhead is called the working chamber. In this space, the water is removed using air pressure. Construction workers can then enter the chamber and excavate the soil.
It is important that the air pressure in the chamber be carefully monitored so the workers do not get the bends.
Pneumatic Caisson
But how do engineers pick which technique to use?
This all depends on the condition of the site and the technology available. These are important decisions to make that only exports can fully handle.
Concrete is as much a part of the urban landscape as trees are to a forest. It’s so ubiquitous that we rarely even give it any regard at all. But underneath that drab grey exterior is a hidden world of compexity.
Concerete is one of the most versatile and widely-used construction materials on earth. It’s strong, durable, low maintenance, fire resistant, simple to use, and can be made to fit any size or shape from the unfathomably massive to the humble stepping stone.
However, none of those other advantages would matter without this : it’s cheap. Compared to oter materials, concrete is a bargain and it is easy to see why if we look at what’s made of.
Concrete has four primary ingredients : Water, sand (also called fine agregate), gravel (aka coarse aggregate) and cement.
A recipe that is not quite a paragon of sophistication, one ingredient falls from the sky and the rest essentially straight out of the ground. But, from these humble beginnings are born essentially the basis of the entire world’s infrastructure.
Actually, of the four, cement is the only ingredient in conrete with anay complexity at all. The most common type used in conrete is know as Portland cement. It’s made by quarried materials (mainly limestone) into a kiln, then grinding them into a fine powder with a few extra herbs and spices.
Cement role :
Cement is a key constituent in a whole host of construction materials, insluding grout, mortar, stucco and of course concrete. A lot of people don’t know this, but every time you say cement when you were actually talking about concrete, a civil engineer’s calculator runs out of batteries.
The cement key role es to turn concrete from liquide to a solid. Portland cement cures not through drying or evaporation of the water, but through a chemical reaction called hydration.
The water actually becomes a part of cured concrete, this is why you shouldn’t let concrete dry out while it’s curing. Lack of water can prematurely sop the hydration process, preventing the concrete from reaching its full strenght.
In fact, as long as you avoid washing out the cement, concrete made with Portland cement can be placed and cured completely under water. It will set and harden just as well (and maybe even better) as if it were placed in the dry.
Aggregate role :
But, you may be wondering « If water plus cement equals hard, what’s the need for the aggregate ? ».
To answer that question, let’s take a closer look by cutting this sample through with a diamond blade. Under a macro lense, is tarts to become obvious how the individual constituents contribute to the concrete.
Aggregates for Concrete
Notice how the cement paste filled the gaps between the fine and coarse aggregate. It serves as a blinder, holding the other ingredients together.
You don’t build structures from pure cement the same way you don’t build furniture exclusively out of wood glue.
Instead we use cheaper filler materials – gravel and sand – to make up the bulk of concrete’s volume. This saves cost, but the agregates also improve the structural properties of the concrete by increasing the strenght and reducing the amount of shrinkage as the concrete cures.
The reason that civil engineers and concrete professionales need to be pedantic about the difference between cement and concrete is this : even though the fundamental recipe for concrete is fairly simple with its four ingredients, there is a trmendous amount of complexity involved in selecting the exact quatities and characteristics of those ingredients.
In fact, the process of developing a specific concrete formula is called mix design. One of the most obvious knobs that you can turn on a mix design is how much water is inluded. Obviously, the more water you add to your concrete, the easier if flows into the forms. This can make a big difference to the people who are placing it. But, this added workability comes at a cost to the concret’s strenght.
How to Improve Collaboration and Communication Between Construction Teams
Effective collaboration and communication between different teams are key when it comes to construction projects. As a project manager, it is your task to ensure that all your teams work like a well-oiled machine. Problems with communication and collaboration can lead to a lot of issues for your project, including scheduling issues, poor work performance, sunk costs, and wasted time. Your management style must go beyond delegating tasks and organizing processes. You need to build relationships between your workers and give them the means to collaborate in an optimal way.
However, achieving the aforementioned goals is not as easy as it might look. In order to be successful, you need to combine smart coaching skills, strategic thinking, and technology. In this article, we will provide you with some practical advice on how to improve the collaboration and communication between different construction teams that work on the same project.
Ensure Open Communication
One of the fundamentals of enabling good internal communication, no matter the number and size of your teams, is to form open communication lines. All team members need to feel that their opinion is respected, valued, and sought-after. Each individual needs to feel like an important part of the team — as a result, information will go up and down the chain without any interruptions.
Project managers need to stay on top of all details surrounding a project, which means that you must have up-to-date information at all times. Keeping communication open will ensure no information is kept from you, which will prevent issues during all phases of your construction project.
Think Strategically
When organizing the communication and relationships between your teams, keep in mind that construction projects tend to take several years to complete. The people you work with need to be willing and able to work together efficiently for a prolonged period of time. On top of that, construction teams that really stick tend to go on working together for their entire careers.
Make sure your team is composed of professionals who are not in this particular field of work only temporarily. Find people who want to keep working in the field, as they will be more motivated to form strong work bonds, communicate efficiently, and keep on improving themselves.
Build Relationships
The work surrounding construction projects usually does not encourage lots of interaction between people. In fact, many workers are solely focused on their own tasks and only communicate with others when it is necessary. In order to build a strong team that collaborates and communicates efficiently, you need to take your people out of their comfort zone and make them interact with one another.
A great way to achieve that is to organize team-building events. It is not necessary to spend money on dinners, hotels, and such — a simple game of soccer outside of working hours can achieve the same thing. Socializing outside of the usual work environment works wonders in building relationships between co-workers. Going out to a bar or organizing a party will strengthen the bonds between your people and ensure your project goes smoothly.
Enable Your Leaders
Team managers ought to be your right-hand people when it comes to implementing your communication and collaboration strategies. They need to be aware of the goals you are trying to reach and actively help you to achieve them. Meanwhile, you should motivate them to practice what they preach and keep them included in the decision-making processes.
If you and your managerial staff are on the same page, executing the plans on this list will be quicker. Leaders must set an example and be the driving force behind any change in work culture and organization. Of course, you need to be aware of the so-called “informal leaders” among your teams. Sometimes, such individuals perform even better as agents of change.
Make Effective Use of Data
Modern technologies have allowed managers to access all types of different project data and use it to improve their work. When it comes to communication and collaboration, you need to properly use the available data in order to improve both. Task management systems can be especially helpful for keeping different teams up to speed on specific aspects of the project.
Use data to track progress and manage any inefficiencies in your teams’ work. Having all teams collaborate using the same datasets will help you with scheduling, optimizing resources, and avoiding any duplicate work.
Use BIM Software Solutions
Perhaps the most effective way to improve collaboration and communication between different construction teams is to utilize BIM tools. Building information modeling (BIM) software started out as a means to generate accurate 3D modeling. However, it has evolved into a full-service suite that can help you with all aspects of managing a construction project.
BIM software allows large teams to seamlessly collaborate on a project in real-time since it uses cloud technology. This way all your workers have access to the same plans, data, and schedule at the same time. Modern BIM solutions have a lot of useful collaboration and communication tools, as well as complex 3D visualizations that can be especially effective when it comes to clash detection, on-site safety measures, and overall risk mitigation.
Conclusion
Even the best construction project manager cannot take on a project entirely by themselves. You need your teams to be motivated, energized, and collaborating in the most optimal way. Communication and teamwork are key to the successful completion of a project, no matter its size and scope. Do not limit yourself to just a person who hands out the tasks. Be a leader and build a team that can go through even the toughest challenges together.
About the Author:
Sofia Jaramillo is an Account Executive for the Pacific Northwest area at Microsol Resources. She was born and raised in Colombia, where she got her Business Administration degree. She moved to New York in 2016 and joined Microsol in 2018 where she has found a new passion within the field of design and construction. In her free time, she likes to practice yoga and run in Central Park.
Water towers are used as a local source of water at times of peak demand where it would not be economical to increase the size of the supply pipeline and add a booster pump installation.
In undu-lating terrain ground-level storage can provide the pressure needed but in areas of flat topography the storage must be elevated. Many shapes and design features are possible but the designer should aim to produce a structure that meets the requirements of both water supply and planning authorities, bearing in mind that it will become a landmark in the community which it serves.
Ancillary equipment including pipework, valves, ladders, instrumentation and booster pumps, if required, can all be hidden in the cylindrical shaft.
The optimum depth/diameter ratios should be determined taking into account the most efficient shape and the needs of the distribution system. It is usually advisable to avoid large pressure fluctuations in distribution that may be caused by draw down or filling in excessively deep tanks.
The main types of water towers are:
1- Concrete water towers:
Concrete water towers are built with capacities up to about 5000 m3. They are usually circular in plan although rectangular concrete towers have been built. The diameter of circular water towers is not usually sufficient to warrant the use of prestressing since cracks can be controlled by applying normal water retaining concrete criteria.
Concrete water towers allow some scope for architectural statement so that the result can be regarded as a visual asset.
Reinforced concrete water tower
Rectangular water towers are designed as small monolithic service reservoirs with the floor slab supported on some form of open column and beam framework or on a hollow vertical shaft, it self founded on a base slab, piled if necessary.
Wind and seismic loads should be taken into account in the design of tank, supports and foundations. Circular concrete water towers allow more scope for different styling from a simple cylinder with a flat base to a sophisticated form such as the hyperbolic-paraboloid of the 39 m high Sillogue tower near Dublin airport built in 2006.
Sillogue Reservoir
In this case the vase shape resembles an inverted version of the nearby control tower. The Intze type water tower (Rajagopalan, 1990) is designed so that bending moments are as near zero as possible at all sections.
Reinforced concrete water tower (Intze type)
2- Welded Steel Water Towers
Relatively small welded tanks have been used for over 100 years for industry and rail transport.These were usually small radius cylinders supported on a framework of steel columns with braces or ties.
Welded steel water towers of capacities up to 15 000 m3are now available and have been widely used all over the world, particularly in North America, the Middle East and the Far East.
These are now constructed of butt welded steel plate in several configurations:spheroids or ellipsoids on tubular columns belled out at the base; cylindrical or spherical shapes with conical bases and supported on wide steel columns which help resist seismic loads and provide space for plant rooms or offices or on a reinforced concrete frame.
Whilst the forms available for welded steel water towers do not offer much scope for architectural treatment, the coatings provide an opportunity for decoration and can be attractive.
Welded Steel Water Towers
3- Segmental Plate Tanks
The type of steel or GRP panel construction can also be used for elevated storage. However, it is unlikely that segmental plate tanks would be used for anything other than industrial or emergency water storage since their poor visual appearance is exaggerated by height.
Where they are used, the bases are placed on a series of beams which are supported on a framework of braced columns.
GPS is a product of the Cold War. Developed by the US military during the President Reagan years, this system consists of a series of 24 satellites in geosynchronous orbit. That is, these satellites remain in the same fixed location in the sky. Out of 360 degrees of longitude, each satellite covers a 15-degree sweep of the globe. They orbit the earth twice each day, broadcasting a timing signal. These signals can be intercepted by ground antennae mounted on ships, tanks, planes—or the buckets and blades of heavy earthmoving equipment.
Though, like all broadcast signals travelling at the speed of light, there is a small-but-measurable time lag between the signals from adjacent satellites. The difference, measured in milliseconds, allows for the triangulation between the ground antennae and the satellites emitting the signal. This triangulation measurement allows for the measurement of the precise location (measured in latitude, longitude, and elevation above sea level) on the surface of the earth where the receiving antennae is currently located. As is true so often in the history of technology, a technical advancement meant for use in war has been modified and adopted for peaceful civilian applications. A system intended to track the movements of men, weapons, ships, and war planes is now used to follow the movements of commercial shipments, find lost hikers, and guide construction equipment.
GPS guides equipment operations through their Automated Positioning Report System (APRS). Using triangulation between the several of the system’s broadcasting satellites allows for positional measurements with accuracies up to 30 centimeters (1 foot). The use of APRS increases this accuracy to 1 centimeter when used in conjunction with GPS. What APRS does is integrate GPS with the equipment’s controls. An APRS replaces the manually operated hydraulic drive cylinders traditionally used to control the movements of an excavator’s arm or dozer’s blade with electronically controlled servo-type valves. These servos send an electric current that creates magnetic field that rotate suspended armatures, that are further connected to fixed flapper arms. These flapper arms provide the linkage to the rotary spools that increase and decrease hydraulic pressure to the hydraulic systems. These are part of the closed-loop hydraulic system that controls the direction, flow rate, and applied pressure of the hydraulic fluid.
Going from individual pieces to equipment to an entire fleet of equipment or trucks is also easily managed by GPS applications. This allows a fleet owner to coordinate and choreograph the movements and activities of an entire fleet of earthmoving equipment and also track the locations of trucks delivering material to the site or hauling dirt away for disposal. Like pieces on a chessboard (or, more accurately, objects in a video game) these activities are tied to an onsite digital terrain model (DTM) of the project site.
This is a three-dimensional (3D) model created by an AutoCAD program, which utilizes a patchwork of connected triangles. The corners of each triangle is defined mathematically by three special coordinates (northing, easting, and elevation). While not a perfect match (no model ever is) to the actual terrain, this geometric surface comes the closes to matching actual surfaces. This is especially true for post construction or excavation surfaces, which tend to be regular and smooth.
Leica excavator machine control solution
The software interacts with the model and the equipment hardware via sensors attached to the business end of the machine (the edge of the dozer blade, the teeth of an excavator bucket, etc.). These sensors continuously record and update the movements of the equipment using the same 3D location system as the DTM. The sensors relay their current location back through the system to the operating controls, which in turn direct the movement of the equipment in accordance with the programmed DTM for the proposed construction surface or excavation grades.
Coordinating all of the mobile GPS sensors on each piece of equipment is a stationary GPS sensor combined with an antenna with a receiver called the base station that is set up adjacent to the operating area. The base station is permanently located over a pre-surveyed reference point, such as a third order benchmark that has been established by ground survey. If necessary, some relative location (manhole rims, street curbs, and building corners, etc.) whose elevation is not exactly known but can be treated as a local datum for the project area can also be utilized for ground antennae setup.
Grader GPS Control
The hardware for these control signals consists of a control box connected to the servo valves via electrical cable, which, in turn, connects to the hydraulic control system that physically moves the equipment. It is the incoming satellite data from the GPS system that tells the equipment where it is. The DTM design files are stored in a compact-flash memory card, memory stick, or accessed externally from data broadcast by the site’s controlled area network (CAN). The database, CAN, and GPS operate in real time to place a blade or bucket exactly where it needs to go and move it so that it accomplishes its task with the need for rework or wasted effort. All three elements, mobile sensors, base sensors, and equipment operator are in continuous communication with each other. The blades and buckets simultaneously move back and forth, up, and down in combination to achieve the desired movement.
Where and When Is GPS Best Used?
The advantages of using GPS guidance systems are legion. Using advanced systems, an operator can increase productivity by greater than 50% compared to purely manual operations. The increase in productivity comes indirectly by the avoidance of having to perform rework at the site. Guided by GPS, an equipment operator can get his cuts and placements right the first time. Furthermore, material wastage is minimized. GPS doesn’t necessarily increase the number of productive hours per day so much as it makes every hour a machine is active much more productive.
This has all sorts of secondary benefits and cost savings. Getting the most out his earthmoving equipment allows a contractor to get the most out of his workforce as well. This reduces labor costs, another costs savings, while reducing the impact of local labor shortages—always an issue in a booming economy with a considerable amount of construction activity. Furthermore, grades and elevations can be checked in real time as the work is being performed. The operator can check his elevation from within his cab as he is working. There is no more need to stop work at regular intervals and have a manual survey performed of the work zone to check its accuracy. In the past, the accuracy-checking task has traditionally relied on a crewmember inside the trenches to manually check depths and slopes. Now with these systems, the need for that task is greatly reduced—thereby cutting job site costs and improving crew safety. This traditional cause of equipment downtime is mostly avoided with the use of GPS.
Giving operators the tools to perform accuracy checks also gives greater responsibility, initiative, and job satisfaction. The additional training that the operators receive has the effect of empowering them, increasing senses of purpose and self-worth. This alone has a marked, if indirect, impact on productivity. By eliminating rework and improving employee morale, any money spent training operators on GPS is a wise investment that pays for itself very quickly. Human factors also show improvement in the area of site safety. The precision guidance and ability to choreograph equipment movement across a busy site improves safety by maintaining safe work zones, avoiding known utility locations, preserving the foundations of existing structures, and maintaining a safe flow of traffic.
GPS systems are often augmented by laser guidance for precise finish work. Lasers can compensate for some of GPS limitations. GPS works best with an open sky and no significant overhead blockage. (For example, GPS is not used for tunneling operations.) Laser guidance stations and targets mounted on equipment blades can work in any outdoor situation, with or without overhead blockage from trees and tall buildings. GPS, however has a much greater effective operating range, limited only by the availability of open sky. Lasers systems are usually limited to about 1,500 feet. GPS can allow for the construction of complicated surface models as well as flat, sloping surfaces. Lasers, being line of site instruments, are usually limited to operations on long, flat, or sloping surfaces. (Though they, too, can build surfaces as directed by a 3D design model represented by a surface AutoCAD file.)
Grade Control System
Productivity can be measured in many ways: time savings, labor costs, material costs, fuel costs, quality bonuses, and finish bonuses. It begins as early as the job layout.
With Machine Control and GPS, you don’t have to wait for someone to stakeout the project or weather that permits someone to stakeout. This allows you to get started sooner. Any design change will also benefit as productivity increase due to not having to wait for restaking.
As the operator starts moving material you will see great value in being able to move the correct amount of material, to the correct location, the first time. This, along with only using the exact amount of material, will translate into a productivity savings.
You can also use GPS by having job layouts of the site so the machines or supervisors’ tablets can have the precise storage locations of materials, job trailers, or site boundaries. This can help having the right things in the correct location or, better yet, not in the way, therefore reducing excessive handling of material.
Drilling Wells Methods – Advantages and Disadvantages
There are several different types of drilling methods. Choosing a method depends on many factors including soil type, underground water level and common practice in every country. Cities using groundwater usually depend upon deep wells. These wells have the advantage of tapping deep and extensive aquifers. All deep wells are drilled wells. The successful digging of drilled wells requires special training, experience, tools and equipment.
The main methods of drilling wells are :
1- Rotary Drilling
The principle of rotary drilling is based upon a rotating drill stem made of lengths of drill pipe about 15 feet long. A bit is attached to a heavy stabilizer or drill collar at the end of the column of drill pipe. The extra weight and larger outside diameter of the stabilizer just above the bit helps to maintain a straight drill hole. The drill stem is hollow and has a drilling fluid of either mud or air circulating down the drill stem out through the nozzles in the bit and up along the outside of the drill stem. The rotating action of the bit breaks up the material and the drilling fluid carries the cuttings to the surface where they settle out in a mud tank.
Advantages:
Speed of Drilling: 5 to 7 times faster than cable tool, capable of several hundred feet per day (dependent on geologic material).
Options of Well Design: Screen can be telescoped or attached, separate screens can be installed, filter packing to enhance formation production, down holle casing hammer method.
Grouting: Oversized borehole requires grouting of annular space surrounding casing, most adaptable to various grout placement methods, practical for grout placement thru casing.
Disadvantages:
Cost of Equipment: 5 times as costly as a cable tool or jetting rig, bit cost and tooling more
Maintenance & Support: Much more extensive and costly than cable tool, higher fuel consumption, water truck needed.
2- Cable Tool Drilling
Cable tool drilling, also known as percussion drilling or spudding, is a widely used well drilling method.
Although it is a slower drilling method, the cable tool is less costly and simpler to operate than a rotary drill rig and is suitable for most geologic conditions.
The cable tool operates by raising and dropping a heavy drill string in the drillhole. The drill string, with bit on the bottom and rope socket (or swivel socket) on top, is suspended in the hole with a cable. The cable is threaded over the crown sheave located at the top of the mast, down to the walking beam, and onto the cable drum where it is stored.
The up-and-down drilling action imparted to the drill stem and cable by the walking beam. The walking beam is pivoted at one end, has a cable sheave at the other end and is connected to the crank gear with a pitman. Rotation of the crank gear causes the walking beam to move up and down. Additional cables called sand lines or casing lines are used to raise and lower casing, bailers, plungers, or other tools.
Advantages:
Inexpensive Equipment: 1/5 cost of rotary rig, less grouting equipment needed, large water truck unnecessary, lower fuel consumption, lower operating cost.
Limited Tooling Required: Bits can be resurfaced, less expensive tooling, used items readily available.
Less Material Removed During Drilling: Generally, no oversized borehole, material removed from casing inside diameter, lighter soils can be bailed from casing.
Repair Work: Cable tool rigs ideal for casing reaming, screen replacement, and
Disadvantages:
Slow Drilling Speed: Bedrock drilling – 1/7 as fast as rotary drilling, Glacial drift drilling – 1/5 as fast as rotary drilling
Depth Limitations with Single Casing String: Driving generally difficult in caving formations, ability to drive casing is limited by tool weight and ground
Outer Casing Needed for Gravel Packing or Full Length Grouting: 3 to 4 inch larger casing needed to maintain annulus and must be extracated during grouting.
Steel Casing Material Only: PVC casing can not be used unlesss installed in an oversized borehole without driving.
3- Auger Drilling
The auger method utilizes spiral augers, usually in 5 foot lengths. The auger stem is turned by a hydraulically-controlled rotary drive head. After drilling the length of an auger, the auger joint is broken and another 5 foot section is added.
Cuttings spiral their way up to the surface where they appear around the borehole, making formation identification relatively simple. If enough clay is present in the formation, the drillhole will remain open when augers are removed.
Dry sands and other caving formations may be a problem for the auger driller and will occasionally result in the loss of long flights of augers. When the auger encounters saturated sand (the water bearing formation to be screened), drilling generally can be continued for a short distance but the hole will not remain open in the saturated formation when the augers are removed.
The auger flight is then broken down and removed from the drillhole after drilling the depth of the well or when changing to another type of drilling operation.
Advantages:
Speed of Drilling: Fast for shallow holes without cobbles or gravel and with low water table, auger/cable tool or jetting combination rigs are common
Limited Equipment: Less expensive than rotary, minimal amount of equipment
Disadvantages:
Limited Depth: Poor results in caving formations, gravel, or high water table, less than 100 feet.
4- Hand Driving
Driven wells are common in many areas, especially around lakes where groundwater may be close to the surface.
Simple installation methods and the low cost of materials make them attractive to homeowners or cottage owners who wish to install their own water supplies.
However, since the well point and casing are driven into the ground, soil conditions are a major factor in suitability of the site. The site must be generally sandy and free of boulders or bedrock to be suitable for a driven well. Hard clay, silt, and very fine sand are generally difficult to drive through.
The installation of a driven well often begins by augering a hole with a hand auger or posthole digger as far as possible. A drive point, consisting of a reinforced well screen with a steel point on the end, is coupled to a 5 foot length of galvanized casing. The most common casing size for driven wells is 1-1/4 inch inside diameter.
A drive cap is placed an the top of the casing and a heavy weight is used to strike the top of the drive cap, driving the point into the ground, When the drive cap is driven close to the ground and driving cannot be continued, another length of casing is added and driving is resumed.
Special drive couplings are used to join sections of casing, Hand driving is usually accomplished by using a weighted driver consisting of a 3 or 4 foot piece of 3 inch diameter pipe capped on the top end. Extra weight is placed in the top portion of the driver. The driver fits over the casing and is guided by it. Another type of driver has a steel rod on the bottom that slides into the casing through a hole in the drive cap.
Raising and dropping the driver is done with the use of handles welded on the sides of the driver. The weighted driver may also be suspended from a tripod and tackle arrangement. The use of a sledge hammer for driving is not recommended since it may result in bent or broken casing from glancing blows.
5- Jetting
Jetting is a drilling method suited for the sandy areas. Jetting remains a popular method for drilling small diameter wells due to its simplicity and inexpensive cost of equipment. Many of the portable, do-it-yourself drilling machines advertised in magazines utilize the jetting method.
Jetting and hollow-rod equipment are quite similar except that drilling water is pumped with the jetting method and the direction of water flow is opposite.
The jetting method involves using a high velocity stream of water to break up the formation material and wash the cuttings away. A chisel-shaped bit with holes to serve as nozzles is attached to the end of a string of hollow drill pipe. Water pressure is provided to the nozzles by using a high-pressure pump.
Water exits from the nozzles and loosens the material being drilled while keeping the bit clean. The bit is raised and lowered and rotated slightly to maintain a round hole. The cuttings are washed to the surface on the outside of the drill pipe and flow into a settling pit or tank.
Cutting samples are easily obtained at this point. A 55 gallon drum is often used for this purpose. After cuttings are allowed to settle, the water is recirculated through the pump, swivel, drill pipe and down to the bit. Jetting can also be done without recirculation of the drilling water; however, a continuous supply of water must be available at the site.
6- Hollow-Rod
Drilling Hollow-rod is referred to as the hydraulic-percussion drilling method.
The hollow-rod is an old drilling method that can be time consuming in some situations, but remains popular due to its simplicity and relatively low cost of equipment.
Most hollow-rod wells are 2 inch diameter, but 4 inch casings are installed occasionally. This method is well suited for sand and soft clay formations with relatively few boulders. It can also be used for drilling rock wells, but progress is slowed considerably. Wells several hundred feet in depth have been completed by the hollow-rod method.
The drill string used in hollow-rod drilling is similar to that used in jetting, except that the chisel bit has a ball check valve in it. Water or a clay-water mixture is kept in the annular space between the drill rods and well casing to help prevent the uncased portion of the hole from collapsing.
The water is supplied to the annulus by gravity intake from a small mud tank. A 55 gallon drum is often used as a settling tank. Drilling is done by lifting and dropping the drill stem and bit. The drill pipe used has triple wall thickness to add weight to the drill string.
The drill string is also rotated slightly by hand during each stroke to maintain a round drill hole. As the bit drops, the ball check opens and mud and cuttings enter the hollow drill rods. On the upstroke, the check valve closes and keeps the cuttings in the drill rods.
Advantages:
Inexpensive Equipment: 1/5 cost of rotary rig, less grouting equipment needed, large water truck unnecessary, lower fuel consumption, lower operating cost.
Limited Tooling Required: Bits can be resurfaced, less expensive tooling, used items readily available, many tools
Less Material Removed During Drilling: Generally no oversized borehole, material removed from casing inside diameter.
Repair Work: Jetting rigs ideal screen replacement and development.
Disadvantages:
Slow Drilling Speed: Bedrock drilling – uncommon, requires heavy drill bar, 1/7 as fast as rotary drilling, Glacial drift drilling – 1/5 as fast as rotary drilling, limited use in gravel formations.
Depth Limitations with Single Casing String: Driving generally difficult in caving formations, ability to drive casing is limited by tool weight and ground
Outer Casing Needed for Gravel Packing or Full Length Grouting: 3 to 4 inch larger casing needed to maintain annulus and must be extracated during grouting.
Steel Casing Material Only: PVC casing can not be used unlesss installed in an oversized borehole without driving.
It is the presence or absence of water that by and large determines how and where humans are able to live.
This in itself makes water an important compound, but when you add in that the availability of water varies enormously in time and space, and that water is an odd substance in terms of its physical and chemical properties, it is possible to see that water is a truly extraordinary substance worthy of study at great length.
To study hydrology is to try and understand the distribution and movement of fresh water around the globe. It is of fundamental importance to a rapidly growing world population that we understand the controls on availability of fresh water.
To achieve this we need to know the fundamentals of hydrology s a science. From this position it is possible to move forward towards the management of water resources to benefit people in the many areas of the world where water availability is stressed.
Water – The ultimate medium for the creation of an architectural masterpiece. Water appeals to all of our senses by adding life to an environment with the added dimensions of sound and movement. When used effectively an architectural fountain can enhance and add focus to a project, distinguishing it from the ordinary.
The Fountain People, believe that the creation of an architectural water feature should have no limitations other than the designer’s imagination. Our many years of experience and in-house design testing facilities provide us with a unique insight into the design of successful water creations.
This Fountain Design Guide has been designed for the sharing of that insight. Our intent is to assist you better understanding the design elements that result in a successful fountain design.
