Insurance when fording mountain rivers.
You only need to cross the ford in boots on your bare feet. In this case, there is less chance of damaging your feet on rocks at the bottom of the river. It is better to remove outer clothing to reduce resistance to the oncoming flow. If the water is warm and the crossing is short, it is better to go through the deep ford without clothes. Place the removed clothing under the top flap of the backpack or tie it in a knot and hold it above your head.
You need to walk in small steps, slowly, feeling the bottom with your feet. Alone, you can cross the river against the current, resting against the bottom with a strong wooden pole. If the stream is stormy, with muddy water, and does not allow you to see the nature of the bottom, it is convenient to use a pole for support, securing it with a rope or cord. If it is difficult to cross alone, you can enter the water with two or three.
SNiP 2.05.06-85: Pipeline crossings through natural and artificial obstacles
General provisions Classification and categories of main pipelines Basic requirements for the pipeline route Structural requirements for pipelines Underground laying of pipelines
6.1. Natural and artificial obstacles include: rivers, reservoirs, canals, lakes, ponds, streams, channels and swamps, ravines, gullies, railways and roads
6.2. Underwater crossings of pipelines through water barriers should be designed based on data from hydrological, geotechnical and topographic surveys, taking into account the operating conditions in the construction area of previously built underwater crossings, existing and designed hydraulic structures that affect the regime of the water barrier at the crossing point, promising dredging and straightening work in a given area where the pipeline crosses a water barrier and requirements for the protection of fisheries resources.
Note: 1. Designing crossings based on survey materials that are more than 2 years old is not permitted without additional surveys.
2. The location of the transition should be agreed upon with the relevant basin departments of the river fleet, bodies regulating the use and protection of water, protection of fish stocks and interested organizations.
6.3. The boundaries of the pipeline underwater crossing, which determine the length of the crossing, are:
for multi-line crossings - a section limited by shut-off valves installed on the banks;
for single-line crossings - a section limited by the high water horizon (HWH) not lower than the 10% supply level.
6.4. River crossing sites should be selected on straight, stable stretches with gently sloping, non-eroded river banks with a minimum width of the floodplain. The underwater crossing should, as a rule, be designed perpendicular to the dynamic axis of the flow, avoiding areas composed of rocky soils. The installation of crossings on rifts is, as a rule, not allowed.
6.5. When choosing a pipeline crossing site, one should be guided by the optimal design method, taking into account the hydrological and morphological characteristics of each reservoir and its changes during the life of the underwater crossing.
When determining the optimal position of the section and transition profile, the calculation should be made according to the criterion of reduced costs, taking into account the requirements for the strength and stability of the pipeline and environmental protection.
6.6. The laying of underwater crossings should be provided with penetration into the bottom of the crossed water barriers. The depth of depth is established taking into account possible deformations of the riverbed and future dredging works.
The design elevation of the top of the ballasted pipeline when designing underwater crossings should be set 0.5 m below the predicted maximum erosion profile of the river bed, determined on the basis of engineering surveys, taking into account possible deformations of the bed within 25 years after the completion of the crossing, but not less than 1 m from natural marks of the bottom of the reservoir.
When crossing water barriers, the bottom of which is composed of rocks, the pipeline depth is assumed to be at least 0.5 m, counting from the top of the ballasted pipeline to the bottom of the reservoir.
If the depth of the underwater crossings is for which there are no mastered technical means for developing trenches, and it is impossible to move the crossing point, which must be justified by the design, it is allowed, in agreement with the relevant basin departments, to reduce the depth of the pipelines and lay them directly along the bottom. In this case, additional measures must be taken to ensure their reliability during operation.
6.7. Transitions of oil pipelines and oil product pipelines through rivers and canals should be provided, as a rule, downstream from bridges, industrial enterprises, piers, river stations, hydraulic structures, water intakes and other similar objects, as well as spawning grounds and places of mass fish habitat.
With an appropriate feasibility study, it is allowed to locate crossings of oil pipelines and oil product pipelines through rivers and canals upstream from the specified objects at the distances given in Table. 4*, while additional measures must be developed to ensure the reliable operation of underwater crossings.
6.8. The minimum distances from the axis of underwater crossings of oil pipelines and oil product pipelines when laying them downstream from bridges, piers and other similar objects and from the axis of underwater crossings of gas pipelines to the specified objects should be taken according to Table. 4* as for underground installation.
6.9. When crossing water barriers, the distance between parallel underwater pipelines should be determined based on engineering-geological and hydrological conditions, as well as the conditions for the construction of underwater trenches, the possibility of laying pipelines in them and the safety of the pipeline in the event of an accident on a parallel one. The minimum distances between the axes of gas pipelines buried in the bottom of a reservoir with a water surface during low-water periods over 25 m wide must be:
at least 30 m for gas pipelines with a diameter of up to 1000 mm inclusive;
50 m for gas pipelines with a diameter of over 1000 mm.
At a multi-line crossing of an oil pipeline and an oil product pipeline, which provides for the simultaneous laying of several main pipelines (main lines) and one backup (reserve line), it is allowed to lay the main pipeline lines in one trench. The distance between parallel lines laid in one common trench and the width of the trench are assigned in the project based on the conditions for constructing underwater trenches and the possibility of laying a pipeline in it.
6.10. The minimum distances between parallel pipelines laid in the floodplain sections of the underwater crossing should be taken as the same as for the linear part of the main pipeline.
6.11*. Underwater pipelines at crossings within the boundaries of the GVV of at least 1% probability must be designed against floating in accordance with the instructions set out in Section. 8.
If the calculation results confirm the possibility of the pipeline floating, then the following should be provided:
on the riverbed section of the crossing - solid (concrete) coverings or special loads, the design of which should ensure their reliable fastening to the pipeline for laying the pipeline by dragging along the bottom;
in floodplain areas - single loads or securing pipelines with anchor devices.
6.12. The width of underwater trenches along the bottom should be determined taking into account the regime of the water barrier, methods of its development, the need for diving inspection and diving work near the laid pipeline, the laying method and conditions for laying the cable of this pipeline.
The steepness of the slopes of underwater trenches should be assigned in accordance with the requirements of SNiP III-42-80*.
6.13. The profile of the pipeline route should be taken taking into account the permissible bend radius of the pipeline, the topography of the river bed and the calculated deformation (ultimate erosion profile), the geological structure of the bottom and banks, the required load and the method of laying the underwater pipeline.
6.14. Artificial bending curves in the channel part of underwater crossings may be provided in particularly difficult topographic and geological conditions. The use of welded bends in the riverbed area is not recommended.
Note. Artificial bending curves at transitions should be located outside the predicted erosion of these areas or be protected by special shore fastenings.
6.15. Shut-off valves installed at underwater crossings of pipelines, according to clause 4.12*, should be placed on both banks at levels not lower than the 10% water supply level and above the ice drift level.
On the banks of mountain rivers, shut-off valves should be placed at levels not lower than the 2% water supply level.
6.16. The project should provide solutions for strengthening the banks in places where the underwater passage is laid and to prevent water flow along the pipeline (installation of upland ditches, clay lintels, jet dams, etc.).
6.17. If the width of water barriers at a low-water horizon is 75 m or more, in places where water barriers cross the pipeline, provision should be made for laying a reserve line. For multi-line systems, the need to build an additional reserve line, regardless of the width of the water barrier, is established by the project.
Notes: 1. When the width of the floodplain is over 500 m at the level of the high water horizon with a 10% probability and the duration of inundation by flood waters is over 20 days, as well as when crossing mountain rivers and the corresponding justification for the project (for example, inaccessibility for repairs), a reserve line It is allowed to provide for crossing water barriers up to 75 miles wide, mountain rivers.
2. The diameter of the reserve thread is determined by the project.
3. It is allowed to provide for the laying of a crossing over a water barrier with a width of more than 75 m in one line, provided that such a decision is carefully justified in the project.
4. If it is necessary to transport viscous oil and petroleum products through a pipeline, the temporary interruption of supply of which is not allowed, provision should be made for laying oil pipelines and petroleum product pipelines through water barriers less than 75 m wide in two lines.
6.18. When designing underwater passages laid at a depth of over 20 m from pipes with a diameter of 1000 mm or more, the stability of the cross-section of the pipe should be checked for the influence of hydrostatic water pressure, taking into account the bending of the pipeline.
6.19. Underwater crossings through rivers and canals with a width of 50 m or less may be designed taking into account the longitudinal rigidity of the pipes, ensuring that the crossing is secured against floating in coastal non-eroded areas by installing weights or anchor devices.
6.20. On both banks of navigable and timber-rafting rivers and canals, when pipelines cross them, signal signs must be provided in accordance with the “Rules for navigation on inland navigation routes” approved by the Ministry of River Fleet of the RSFSR, and the “Rules for the protection of main pipelines” approved by the Council of Ministers of the USSR.
6.21. In swamps and wetlands, underground installation of pipelines should be provided.
As an exception, with appropriate justification, it is allowed to lay pipelines along the surface of the swamp in the body of the embankment (ground installation) or on supports (above-ground installation). At the same time, the strength of the pipeline must be ensured, its overall stability in the longitudinal direction and against floating, as well as protection from thermal effects in the event of a rupture of one of the threads.
6.22. With appropriate justification, when laying underground pipelines through swamps of types II and III with a length of over 500 m, it is allowed to provide for the laying of a reserve line.
6.23. The laying of pipelines in swamps should, as a rule, be laid in a straight line with a minimum number of turns.
At turning points, elastic bending of pipelines should be used. Above-ground installation in swamps should be provided in accordance with the requirements set out in Section. 7.
6.24. The laying of pipelines when crossing swamps, depending on the thickness of the peat layer and the water regime, should be provided directly in the peat layer or on a mineral base.
It is allowed to lay pipelines in embankments with uniform load transfer to the peat surface by laying a lining of small forests. The lining must be covered with a layer of local or imported soil at least 25 cm thick, on which the pipeline is laid.
6.25. The dimensions of the embankment when laying a pipeline with a diameter of over 700 mm in it with a calculated difference in positive temperatures in this area should be determined by calculations that take into account the influence of internal pressure and longitudinal compressive forces caused by changes in the temperature of the pipe metal during operation.
6.26. The smallest dimensions of the embankment should be taken:
the thickness of the soil layer above the pipeline is at least 0.8 m, taking into account soil compaction as a result of settlement;
the width of the embankment at the top is equal to 1.5 times the diameter of the pipeline, but not less than 1.5 m;
embankment slopes depending on the properties of the soil, but not less than 1:1.25.
6.27. If peat with a degree of decomposition of organic matter less than 30% is used to construct a mound, it is necessary to provide a protective mineral coating on top of the peat 20 cm thick.
The embankment of peat and mineral soil must be strengthened to protect against erosion and weathering. Materials and methods for strengthening the embankment are established by the project.
6.28. When designing an embankment, provision should be made for the installation of culverts: trays, open ditches or pipes. The bottom of culverts and adjacent slopes must be reinforced.
The number and size of culverts are determined by calculation taking into account the terrain, catchment area and intensity of surface water runoff.
6.29. Pipeline sections laid in an underwater trench through swamps or flooded floodplains, as well as in flooded areas, must be designed against floating (for position stability). To ensure position stability, special structures and devices for ballasting (weight coatings, ballasting devices using soil, anchors, etc.) should be provided.
6.30. When securing the pipeline with anchor devices, the anchor blade should not be in a layer of peat, peaty soil or loess, silty sand or other similar soils that do not provide reliable fastening of the anchor, as well as in a layer of soil whose structure may be subject to destruction or loss of cohesion as a result of thawing , erosion, weathering, underwork or other reasons.
6.31*. Pipeline crossings across railways and highways should be provided in places where roads pass along embankments or in places with zero marks and, in exceptional cases, with appropriate justification in road excavations.
The angle of intersection of the pipeline with railways and roads should, as a rule, be 90 °. Laying a pipeline through the body of the embankment is not allowed.
6.32*. Sections of pipelines laid at crossings through railways and highways of all categories with improved coverage of capital and lightweight types must be provided in a protective case (casing) made of steel pipes or in a tunnel, the diameter of which is determined from the conditions of the work and the design of the crossings and must be larger the outer diameter of the pipeline by at least 200 mm.
The ends of the case should be brought out at a distance:
a) when laying a pipeline through railways:
from the axes of the outer paths - 50 m, but not less than 5 m from the bottom of the embankment slope and 3 m from the edge of the excavation slope;
from the extreme drainage structure of the roadbed (ditch, upland ditch, reserve) -3 m;
b) when laying a pipeline through highways - from the edge of the roadbed -25 m, but not less than 2 m from the base of the embankment.
The laying of the pipeline communication cable in the sections where it crosses railways and roads must be carried out in a protective case or separately in pipes.
6.33*. At underground passages of gas pipelines through railways and roads, the ends of the protective cases must have seals made of dielectric material.
At one end of the case or tunnel, an exhaust candle should be provided at a horizontal distance, m, not less than:
from the axis of the extreme track of public railways……………….. 40
the same, industrial roads …………………………………………………………… 25
from the base of the roadbed ……….. …………….. 25
The height of the exhaust candle from ground level must be at least 5 m.
6.34*. The depth of sections of pipelines laid under the railways of the general network must be at least 2 m from the base of the rail to the upper part of the protective case, and in recesses and at zero marks, in addition, at least 1.5 m from the bottom of the ditch, tray or drainage .
The depth of pipeline sections laid under roads of all categories must be at least 1.4 m from the top of the road surface to the upper part of the protective casing, and in recesses and at zero marks, in addition, at least 0.4 m from the bottom of the ditch, drainage ditch or drainage.
When laying a pipeline without protective casings, the above depths should be taken to the upper generatrix of the pipeline.
The burial of pipeline sections under highways on the territory of compressor stations and oil pumping stations is accepted in accordance with the requirements of SNiP II-89-80*.
6.35. The distance between parallel pipelines in the sections of their transitions under railways and roads should be determined based on soil conditions and work conditions, but in all cases this distance must be no less than the distances accepted for underground laying of the linear part of main pipelines.
6.36. The intersection of pipelines with the rail tracks of electrified transport under switches and crosses, as well as in places where suction cables are connected to the rails, is not allowed.
6.37. The minimum horizontal clear distance from the underground pipeline at the points of its passage through the railways of the general network should be taken, m, up to:
switches and crosspieces of the railway track and places of connection of suction cables to the rails of electrified railways…………………………………………………………………………………………………………………… ………………..10
switches and crossings of the railway track in heaving soils…………..20
pipes, tunnels and other artificial structures on railways……. thirty
Overhead laying of pipelines Calculation of pipelines for strength and stability Environmental protection Protection of pipelines from corrosion Technological communication lines of pipelines Design of pipelines for liquefied hydrocarbon gases Materials and products Appendix. Recommended
An insurance system for fording mountain rivers.
If crossing mountain rivers is difficult, it is better to wade across the railings. The figure below shows the organization of such a crossing and insurance for its participants.
Throwing logs across the river.
When floating a log, you need to determine in advance the point on the opposite bank (large stone, tree, etc.) at which the top of the log will rest. After laying the log, the first participant in the crossing without a backpack (with a belay from the shore and an auxiliary safety rope attached to the chest harness) walks along the log to the other bank and, higher from the log along the water flow, pulls the railing. In this way, the crossing and the necessary insurance for those crossing are organized.
What you need to know before crossing the river
Often during hiking, especially in mountainous areas, there are rivers along the routes of tourist travelers, which can become a serious obstacle for an unprepared person. To organize a river crossing, you first need to evaluate it according to four criteria:
- width;
- depth;
- bottom surface;
- flow.
A strong current, even with a small depth and width of the river, will create additional difficulties when crossing. In the case of a mountain river, the criteria are even more important, since they can change noticeably (soft sign) depending on the meteorological situation (rain, thunderstorm, melting snow, etc.).
Attention! It is unsafe to ford a river with a strong current (current with a speed of more than 3 m/s). In this case, you should refuse the crossing.
Let's take measurements
In order to determine the flow speed, you can use the simplest arithmetic equation: V=S/T. In the equation, V is the speed of the current, S is the path traveled by the object, and T is the time it took the object to travel this path. It is most convenient for two people to organize such measurements on the ground. To do this you need:
- you and your companion stand parallel to the river at a measured distance S from each other;
- throw an object into the water, for example a small piece of wood;
- detect the time T during which the object will cover a section of the measured path S.
The recommended path S between measurement participants should be at least 10 meters. This value will allow you to find out the speed without significant errors.
Formula for calculating current speed
You can find out the depth of the river using several indicators. If the water hazard is not very wide, it will be enough to arm yourself with a branch of the maximum available length that can be found nearby. After, having probed the bottom in several places, find the maximum result by examining the border of the moistened section of the branch. This method will also allow you to find out the bottom surface, thanks to the remains of sand or other substance at the end of the stick. In cases where the width of the river does not allow measuring the depth from the bank, you will need to navigate by visual indicators. For example, small ripples or waves with the formation of so-called “wings” on the surface will mean aground. A calm water surface in the presence of at least minimal wind (almost calm) indicates great depth. Typically, this behavior is typical for a river bed with a depth of 2-3 meters.
Method for measuring the width of a river
If you do not often take your laser tape measure with you on a hike, then you will be faced with the question of how to find out the distance to the other bank, that is, the width of the river. For this there is a not very accurate, but very simple method, the knowledge of which will be completely sufficient on a hike. The method is based on a proportional change in the angle of the field of view and distance. To organize such measurements you need:
- pick up a blade of grass or a thin straight branch;
- select two stationary objects on the opposite bank, located at a distance from each other (trees, stones or relief features that can act as conditional points);
- take a branch or blade of grass and, with outstretched arms (constantly watch this), position it so that its ends visually touch conventional points (selected objects);
- Having broken the branch in half as evenly as possible, take it in the same way and begin to move back until the objects are again at its ends.
- measure the distance you travel from the location at the start and end of the event.
This distance will be the width of the river. Based on such data, you can calculate the required amount of materials to organize a crossing, for example, using logs.
How to find out the width of a river
The method can be used in a different order, using a blade of grass that was initially folded in half and, when approaching the river, unfold it to its full size.
Suspended crossing over mountain rivers.
If the above mentioned crossing methods are not possible due to the excessively rapid flow of the river or its width, an overhead crossing is used. For long suspended crossings, to avoid excessive tension on the rope and breakage, use a double rope. When sliding down an inclined rope crossing, you should not grab the rope; you may get burned. To avoid hitting the shore, it is forbidden to descend head first.
Attaching the chest harness of a person crossing with a carbine to the supporting rope is mandatory. Since in any case the rope will sag in the middle of the river, an auxiliary rope is attached to the person crossing - it is used to pull him to the shore. At the suspended crossing, backpacks, ice axes, and other equipment are transported separately.
Basic rules for crossing mountain rivers.
1. Before crossing, it is necessary to carefully reconnoiter the banks. Assess the situation, taking into account the strength and speed of the flow, the depth and topography of the riverbed, the possibility of using supports, select materials and equipment for organizing the crossing. 2. Determine the method of crossing. 3. Select the place and time of the crossing. 4. Set up an observation place from where the entire crossing can be seen and you can direct it. 5. In a particularly difficult situation, use only double insurance. 6. Before you start crossing, you should check the reliability of the anchor points and the condition of the ropes. 7. Let the most experienced person go first to the crossing.
8. When crossing a pole, you should rest it upstream. 9. When moving with the organization of belaying with railings, you must move to the side of the railing, downstream. 10. Do not use a grasping knot when crossing. 11. Do not allow two or more people to cross at the same time. 12. At the suspended crossing, backpacks, ice axes, and other equipment are transported separately. 13. Reliable insurance and self-insurance are required. 14. When crossing in a group, the strictest discipline and order are needed.
Based on materials from the book SURVIVAL. Koleda S.I., Drachev P.N.
River crossing and difficult sections
An experienced tourist, physically and emotionally strong and resilient, should go first. The person following him must be able to swim so that he can provide assistance if necessary. Only after the “pioneer” reaches the other shore does the entire group cross the water area. It is better to send those unsure of their abilities after the strong participants in the hike.
When fording a stream in a difficult area, you will need a pole and 2 ropes. Each of them will be held by 2 people. The first tourist must fasten himself to the main and auxiliary ropes. The people holding the equipment should spread out so that the main rope runs upstream and the secondary rope goes downstream. With this approach, if the “pioneer” falls, then one rope will hold him and prevent him from sliding, and the other will help pull him to the shore.
The rest of the hike participants cross the pond facing the water run. The last person unties the rope as the crossing is completed.
