What is the stiffness of the pipe sn4. Useful information. Pvc pipes and pipes korsis for sewerage

Corrugated sewer pipes are now used more often than concrete or metal. They have the same high reliability and durability in operation. And they are installed much easier due to their low weight. Fewer workers are involved in the installation of piping systems.

Types of plastic pipes

There are two-layer and one-layer corrugated pipes. Two-layer products are more durable and can withstand ground pressure more easily. If installed in a sewer underground.

In turn, two-layer sewer elements are classified according to the materials of manufacture:

Polyvinyl chloride products (PVC). Used in industrial sewers. In the gutters of private houses.

Polypropylene (PP). Of these, a drainage, storm or external system is mounted. Excellent resistance to temperature fluctuations.

Low pressure polyethylene (HDPE). Excellent for mounting and temperature extremes.

For sewer pipes, polymer products are an excellent conductor. Of these, drainage systems are being built, central sewerage systems are being laid. There are several types of polymer products. They differ in the size of their diameters. For example, 400 mm., 315 mm., 160 mm. These are the most popular options for installations of different systems.

Corsis SN8

The Korsis SN8 pipe is suitable for the manufacture of a non-pressure (gravity) system. The product is made in corrugated and double-layer. Highest quality. PP pipes are durable and easy to install. The elements are produced in Russia, but at the same time they use Italian technology.

Scope of use of Corsis

Corrugated pipe SN8 is made in black on the outside and in white or blue on the inside. Made of two layers: outer and inner. The outer layer is a protection against deformation under mechanical stress. The inner layer is made smooth and does not allow dirt to accumulate on the walls.

Double-layer pipe SN8 is used for the following works:

When carrying out sewer structures.
As passage elements for the restoration of roads in the unpaved bed.
For drainage of melt and storm water.
For mounting drainage systems.

Characteristics of Corsis

PP sewer elements are made of polyethylene or polypropylene. These are different types of pipes, although they differ little. The differences are in the ring stiffness (SN). Polyethylene Korsis has a hardness of 4, 6 or 8. And polypropylene Korsis PRO has a hardness of 12 or 16. In addition, there are differences in operating and installation temperatures. Polyethylene can withstand 0- + 40. And polypropylene is 0- + 95.

PP SN8 pipe has standard sizes - from 6 to 12 meters. Two-layer polyethylene SN8 has a low stiffness class. It is used for the manufacture of stormwater or sewer structures. Laying is carried out to a maximum depth of 10 m.

The plastic SN8 is a highly impact-resistant pipe. It is resistant to chemical and mechanical stress. Ease of installation is ensured by the ability to bend the elements. Since plastic is elastic. Corrugated products can be easily transported by car and stored anywhere. They fit easily into a standard car body without making it too heavy.

Varieties by size

SN8 double-layer plastic elements are divided into standard sizes. Most often they are characterized by their outer diameter: from 120 to 1200 mm.

In private buildings, pipelines using corrugated elements are laid in trenches. During installation, it is recommended to adhere to the established rules:

Before placing the flushing pipe in the sewer, each section of it is carefully checked for defects and shortcomings.
Work is carried out at a certain temperature - at least +15 degrees.
Before placing pipes in the trench, it is necessary to place them around the perimeter of the ditch. Distribute should be in the direction that is a slope towards the highway.

Everything is thoroughly cleaned on the sockets and ends of the elements. So that there is no dirt on them at all. O-rings are required to install corrugated pipes. This is an important editing feature that should not be forgotten.

Such structures have a ribbed surface that increases their strength. Due to this form, corrugated pipes are recommended to be laid on complicated trench sections. Which are located inside roads or in places with strong ground pressure. The high strength and elasticity of the two-layer drainage elements makes it possible to use them even in places with bends and sharp turns.

The smooth surface of the product (inner) eliminates the appearance of dirt build-up in the system. This further extends the service life of the pipelines.

Even before starting work, you should find out: what kind of load the selected plastic element will withstand. This indicator depends on the stiffness. SN8 has average. Withstands more than 12 kilonewtons per square meter.

Increased indicators of pipe cross-sections

To equip highways, rainfall or ground outlets, drainage products with large sections are used. For example, pipe SN8 400 mm. The use of 315 and 160 mm is allowed. But you must understand that the 160 SN8 pipe belongs to the single-layer type. And it is better to use such a design under more benign conditions.

Elements in 400 mm. used at serious depths. They are even allowed to be installed not in trenches, but in open ditches. Such systems are excellent at both low and high temperatures. Are not exposed to chemical attack. Installation is permissible even in the ground, where there are slopes and relief thresholds. Plastic is able to adapt to any bend. At the same time, the products will not lose their qualities.

The winding method is used for the production of specially designed pipes, including pipes of variable diameter and / or variable wall thickness; pipes with a profiled wall and various layer materials; elastic hoses reinforced with a spiral supporting frame, and others. The advantages of the winding technology mainly lie in the ease with which the same type of technological methods and equipment can ensure the production of products that are diverse in design and dimensions.

Fig. 1. Equipment for the production of pipes KORSIS PLUS

So, shown in Fig. 1 tooling, despite its complexity, allows in a matter of minutes to switch from the production of a pipe with a diameter of 600 mm to the production of a pipe with a diameter of 2000 (3000) mm. In this case, one pipe can have a smooth wall of almost any thickness, and the next one - a wall specially profiled.

Polymer pipes with a profiled wall are intended for underground construction of free-flow systems drainage, sewers and drainage, the main requirement for which is ring stiffness... The design of such pipes allows saving up to 2/3 of the material compared to a smooth-walled pipe of the same ring stiffness.

Double-layer pipes used in gravity sewerage systems. The outer layer of the pipe is a corrugated surface, the numerous ribs of which create high rigidity to resist high loads. The inside of the pipe is made of high quality polyethylene, which has high hydraulic properties and allows water to drain freely and without stagnation. The inner surface is flat, so water does not accumulate in the depressions formed by the ribs. The presence of stiffeners favorably distinguishes this type of drainage pipes from analogs and makes their choice a priority for installation in places subject to strong mechanical loads.

Double-layer corrugated pipes Korsis and Perfokor

Double-layer corrugated pipes Corsis are made of polyethylene, which is impact-resistant even at low temperatures. There are two main stiffness classes of corrugated double-layer pipes Korsis - these are SN6 and SN8, which have a ring stiffness of 6 kN / m2 and 8 kN / m2, respectively. In other words, pipes with stiffness class SN6 can be laid to a depth of 6 meters, and with class SN8 up to 8 meters. The minimum laying depth for both types of pipes is 1 meter. The connection of the pipes is hermetically sealed, it takes place by butt welding, or using a coupling and an O-ring. The versatility of sizes allows you to connect Korsis pipes with other elements of the drainage system, and a large selection of fittings and accessories allows you to create systems of any complexity.

To solve the problem of soil drainage in conditions of strong mechanical loads, the most effective solution would be to lay two-layer Perfokor drainage pipes. The structure of the Perfokor pipe is similar to the structure of the Korsis pipes, corrugated on top and with a smooth layer inside. Their main difference is the presence of perforation, which is made in the form of cracks and allows you to collect unwanted water accumulated in the soil and take it to the right place (drainage well, reservoir, ditch). Smooth inner surface prevents pipe clogging and ensures fast water transport. There are several stiffness classes for two-layer Perfokor pipes: SN4, SN6 and SN8 - they are designed for a maximum depth of 4, 6 and 8 meters, respectively. On sale there are both full drainage pipes, the holes of which are evenly distributed over the entire surface, and semi-drainage pipes, only the upper part of which has holes, and the base is solid. The full-drainage option is used in cases when it is necessary to lower the groundwater level, and the semi-drainage option is used to collect and remove the top water. The most widespread popularity of Perfokor pipes was obtained in the improvement of personal plots, drainage of building pounds, as well as in road construction.

FD Plast double-layer corrugated pipe

The assortment includes corrugated two-layer pipes FD Plast... Inner diameters range from 110 to 800mm and stiffness class SN8-SN9. They are made of low pressure polyethylene (HDPE) and are characterized by resistance to aggressive environments and durability. The depth of these pipes can be up to 15 meters. FD Plast corrugated pipes have high quality workmanship at a relatively low price.

Price for double-layer corrugated pipe with SN8 socket

External diameter, mm	Internal diameter, mm	Price, l.m.
110	94	from 150 rubles.
133	110	from 188 rub.
160	136	from 268 rub.
190	160	from 312 rub.
200	171	from 358 rub.
230	200	from 455 rub.
250	216	from 567 rub.
290	250	from 767 rub.
315	271	from 871 rub.
340	300	from 1096 rub.
400	343	from 1357 rub.
460	400	from 1609 rub.
500	427	from 2061 rub.
575	500	from 2295 rub.
695	600	from 3130 rub.
923	800	from 5832 rub.

Two-layer pipes Polytek

In addition, double-layer corrugated pipes are commercially available. Polytek with inner diameters from 100 to 315 mm and stiffness class SN8. They are made of polyethylene and have high ring stiffness, chemical resistance to alkalis and acids, low weight, as well as durability.

Double-layer pipes X-stream (Wavin)

Also, the product range is represented by double-layer pipes X-stream company Wavin, which are made of polypropylene and have a stiffness class SN8. Due to their high elasticity, X-stream pipes can withstand high dynamic and static loads, while maintaining complete tightness of the joints.

Standard sizes of pipes PROTEKTORFLEX ®

The classification of free-flow pipes is traditionally made not according to the value of the standard dimensional ratio ( SDR), and according to the class of ring stiffness ( SN). The fundamental difference SDR and SN is that SDR is the geometric characteristic of the pipe (the ratio of the outer diameter of the pipe to the thickness of its wall), while SN is a mechanical characteristic.

Ring stiffness SN allows you to judge the properties of a pipe to resist soil pressure and is defined as the load on the pipe (kN / m2), at which the pipe is compressed by 3% of its diameter. The magnitude SN depends not only on the diameter of the pipe and the thickness of its wall, but also on the modulus of elasticity E material in compression.

The marking of the pipe for laying the cable line must include the pipe diameter D, wall thickness e, ring stiffness SN, the ultimate pulling force F 1MAX, long-term admissible temperature T, at which the ring stiffness remains at least the entire service life of the cable.

Options D, e, SN and T should be monitored when supplying pipes to facilities under construction. Meaning F 1MAX may be required later - already at the stage of work on tightening the pipes into the borehole, when the operator of the HDD rig will control the actual pulling force F and interrupt the process of pulling the beam from N pipes in case F > 0,5 · N · F 1MAX in order to prevent pipe breakage.

Selection of pipe diameter and wall thickness

Figure 1 shows a pipe with an outer diameter D and wall thickness e, inside which the cable is laid with an outer diameter d... According to regulatory documents, when choosing the outer diameter of pipes, the following rule should be adhered to:

Pipe wall thicknesseis determined by mechanical calculations based on basic information about pipe laying conditions and is based on the concept of ring stiffnessSN.

Figure 1. Polymer pipe with cable: without ground pressure ( a), with soil pressure ( b)

The relationship between wall thickness and ring stiffness is established by the expression:

where E- the modulus of elasticity of the pipe material in compression.

Pipe wall thicknesse (mm) depending on the pipe diameterD (mm) and ring stiffness SN(kN / m 2)

External diameter pipesD , mm			Ring stiffnessSN , kN / m 2
			12	16	24	32	48	64	96
			Pipe wall thicknesse , mm
32*	PROTEKTORFLEX® ST, BK, NG		-	-	2	2,2	2,5	2,7	3,1
40*			-	2,2	2,5	2,8	3,1	3,4	3,9
50*			2,5	2,8	3,1	3,4	3,9	4,3	4,8
63*			3,2	3,5	4	4,3	4,9	5,4	6,1
75*			3,8	4,2	4,7	5,2	5,9	6,4	7,2
90*			4,6	5	5,7	6,2	7	7,7	8,7
110			5,6*	6,1	6,9	7,6	8,6	9,4	10,6
125			6,3*	6,9	7,9	8,6	9,8	10,7	12
140			7,1*	7,8	8,8	9,6	10,9	11,9	13,5
160			8,1	8,9	10,1	11	12,5	13,6	15,4
180			9,1	10	11,3	12,4	14	15,3	17,3
200		PROTEKTORFLEX® PRO, OMP	10,1	11,1	12,6	13,8	15,6	17	19,3
225			11,4	12,5	14,2	15,5	17,6	19,2	21,7
250			12,7	13,9	15,7	17,2	19,5	21,3	24,1
280			14,2	15,5	17,6	19,3	21,8	23,9	27
315			15,9*	17,5	19,8	21,7	24,6	26,8	30,4
355			18	19,7	22,3	24,4	27,7	30,3*	34,2*
400			20,2	22,2	25,2	27,5	31,2	34,1	38,5
450			22,8	24,9	28,3	31	35,1	38,3	43,4
500			25,3	27,7	31,5	34,4	39	42,6	48,2
560			28,3	31	35,3	38,6	43,7	47,7	54
630			31,9	34,9	39,7	43,4	49,2	53,7	-

* Produced in a single layer

Note: The outer diameter of PROTEKTORFLEX® PRO pipes is indicated without taking into account the thickness of the protective coating.

There are two main ways of placing pipes in the ground - this is laying in a pre-prepared trench (Figure 2 a) or pulling pipes into the ground into a prepared channel, often performed by horizontal directional drilling (Figure 2 b). In both cases, the design of the pipe is based on the concept of ring stiffness SN, on the basis of which it is possible to determine not only the thickness of the pipe wall, but also the ultimate tensile force of the pipe when it is pulled into the borehole.

Figure 2. The main methods of laying polymer pipes: trench ( a), HDD method ( b)

Selection of pipe ring stiffness

The vertical pressure of the soil (and transport) on the pipe is the force applied to the pipe and tends to cause its ovality, however, the resulting “ground rebound” located on the sides of the pipe tends to return the shape of the pipe cross-section to the original round one. The dense soil on the sides of the pipe is a factor that increases its mechanical strength.

where q and SN are measured already in kN / m2, and E " S- the factor of soil stiffness, which is called the secant modulus of the soil (MPa).

Cutting soil module E " S depends on the type of soil with which the pipe is filled up and the degree of its compaction. As a rule, sand is used for these purposes, and then it is recommended to use the data in the table.

Backfill depth H, m	The condition of the sand with which the pipe is filled
	Unconsolidated	Compacted manually	Compacted mechanically
	*Cutting soil module E "* s, MPa**
1	0,5	1,2	1,5
2	0,5	1,3	1,8
3	0,6	1,5	2,1
4	0,7	1,7	2,4
5	0,8	1,9	2,7
6	1,0	2,1	3,0

The vertical load on the pipe (kN / m2) consists of three components:

where q r- load from the weight of the soil (kN / m 2); q AT- load from vehicles (kN / m 2 );

The load from the soil in the most unfavorable case, when the entire column of soil presses on the pipe with a height H,

where ρ r- specific gravity of soil (usually no more than 2 t / m 3); g = 9.81 m / s 2 - acceleration of gravity; H- the depth of the pipe location underground (m).

Transport load can be defined as

Results of calculating the maximum pipe laying depth N are given in the table below. It can be seen that when laying pipes in trenches, it is dangerous to use pipes with an annular stiffness less than 8 and there is no need to use pipes with SN more than 64.

Limiting depthH (m) when laying in an open way under lawns/ squares / highways

SN, kN / m 2	Cutting soil module E " s , MPa
	0	0,5	1	1,5	2	2,5	3
	Maximum laying depth H, m
4	0,4 / -	0,8/-	1,3/-	1,7/-	2,1/-	2,5/-	2,9/-
6	0,7 / -	1,1/-	1,5/-	1,9/-	2,3/-	2,7/-	3,1/-
8	0,9/-	1,3/-	1,7/-	2,1/-	2,5/-	2,9/-	3,3/-
12	1,3/-	1,7/-	2,1/-	2,5/-	2,9/-	3,4/-	3,8/-
16	1,7/-	2,2/-	2,6/-	3,0/-	3,4/-	3,8/1,7	4,2/2,4
24	2,6/-	3,0/-	3,4/0,7	3,8/1,8	4,3/2,5	4,7/3,0	5,1/3,6
32	3,5/0,9	3,9/1,9	4,3/2,5	4,7/3,1	5,1/3,7	5,5/4,2	5,9/4,7
48	5,2/3,8	5,6/4,3	6,1/4,8	6,5/5,3	6,9/5,8	7,3/6,2	7,7/6,7
64	7,0/5,9	7,4/6,4	7,8/6,8	8,2/7,3	8,6/7,7	9,0/8,2	9,4/8,6

Choosing the Ultimate Strength of Gravity

When laying by the HDD method, pipes are subjected to two types of influences: first, longitudinal tensile forces F, which arise when the pipe is pulled into the borehole; secondly, the vertical pressure of the soil and transport during the operation of the pipe. The choice of ring stiffness and wall thickness is mainly determined by the tensile forces.

Pipe pulling force F creates friction forces arising from the weighting of the pipe under the action of the soil piled on the pipe due to poor fastening of the walls of the borehole with drilling fluid (bentonite) or even complete impossibility of fastening (quicksand, difficult scenario).

where qr- weight of soil in kN / m2; DEKV- the equivalent diameter of the string of pipes being pulled through; µ - coefficient of friction of the polymer pipe against the ground (usually equal to 0.2).

Checking the admissibility of pulling efforts F arising when the pipe is tightened (pl nets of pipes) into the borehole is performed as follows

where 0.5 is the safety factor; N- the number of pipes in the string (one or four); F1MAX is the ultimate tensile force of each pipe (kN), which can be found as

where D and e- outer diameter and pipe wall (in mm); σ - the yield point of the pipe material (MPa).

Ultimate gravity F1MAX are shown in the table below

Ultimate pipe tensile forceF 1MAX (kN) depending on pipe diameter D (mm) and ring stiffnessSN(kN / m 2 )

External diameter pipes D, mm			Ring stiffness SN, kN / m 2
			4	6	8	12	16	24	32	48	64	96	128	192	256
			Ultimate Strengthening of Pulling F *1MAX* , kN
32	PROTEKTORFLEX® ST, BK, NG		2,3	2,6	2,9	3,2	3,5	4,0	4,3	4,9	5,3	5,9	6,4	7,1	7,6
40			3,6	4,1	4,5	5,1	5,5	6,2	6,8	7,6	8,2	9,2	10	11	12
50			5,7	6,4	7,0	7,9	8,6	9,7	11	12	13	14	16	17	19
63			9	10	11	13	14	15	17	19	20	23	25	27	29
75			13	14	16	18	19	22	24	27	29	32	35	39	42
90			18	21	23	26	28	32	34	38	42	47	50	56	60
110			27	31	34	38	42	47	51	57	62	70	75	83	90
125			35	40	45	50	55	60	65	75	80	90	95	105	115
140			45	50	55	62	68	75	83	93	100	115	125	135	145
160			60	65	70	80	90	100	110	120	130	145	160	175	190
180			75	85	95	105	115	125	135	155	170	185	200	225	240
200		PROTEKTORFLEX® PRO	90	100	115	125	140	155	170	190	205	230	250	275	295
225			115	130	140	160	175	195	215	240	260	290	315	350	375
250			140	160	175	200	215	245	265	300	320	360	390	430	465
280			180	200	220	250	270	305	330	370	400	450	485	540	580
315			225	255	280	315	345	385	420	470	510	570	615	685	735
355			285	325	355	400	435	490	535	600	650	725	780	870	935
400			365	410	450	510	550	625	675	760	820	920	990	1100	1180
450			460	520	570	640	700	790	855	960	1040	1160	1260	1400	1500
500			570	640	700	790	865	975	1060	1190	1290	1440	1550	1720	1850
560			710	805	880	990	1080	1220	1330	1490	1610	1800	1950	2160	2320
630			900	1020	1110	1260	1370	1550	1680	1880	2040	2280	2460	2730	2940

Note. When pulling a polymer pipe into the ground, it is recommended to limit the tensile forces to a safe level of 0.5 F 1MAX .

The limiting length of the pipe that can still be pulled into the borehole without the risk of unacceptable stretching or even breakage,

Selection recommendationsf " coefficient depending on the drilling scenario

The table below shows estimates of the limiting length of the borehole. L HDD depending on the number of pipes and drilling scenario.

Estimates of the limiting length of the borehole L HDD(m) depending on the number of pipes N

SN, kN / m 2	N = 1			N = 4
	The scenario in which the channel is being drilled
	Heavy	Average	Light	Heavy	Average	Light
	Drilling channel limiting length L *HDD* , m
4	38	190	303	26	131	209
6	43	214	342	29	147	236
8	47	235	375	32	162	258
12	53	264	423	36	182	291
16	58	289	462	40	199	318
24	65	324	518	45	223	357
32	70	352	564	49	243	388
48	79	396	633	55	273	436
64	86	428	685	59	295	472
96	96	479	766	66	330	528
128	103	517	828	71	356	570
192	115	574	918	79	395	632
256	123	617	987	85	425	680