1、 overturning; anti-slip; stabilityPrefaceSurface coal mine hoist room is an important part of the production system.Tied with Derrick important structures for the upgrading of the system.With the increase in coal production capacity, upgrading the previous single-mode can no longer meet the needs of
2、 modern production, the progressive development of multi-round, multi-rope lifting way.Enhance the ropes pull also increased and role of tension based on the hoist is also growing.The past, the basis of a single Shengti lift weight alone can meet the requirements to enhance the stability of machine.
3、Requirements may construct the foundation made of plain concrete foundation.Mine is a large machine used in multi rope, then part of the foundation alone hoist weight falls far short of basic stability.Need to broaden the basis of weight or other technical measures using other anchor.Thereby enhanci
4、ng machine-based design raises new problems and new demands, more and more attention by the engineering and technical personnel.1 Hoist-based stress analysis1.1Determination of hoist rope tensionWire rope at one end and raise the container skip or cage connected to the other end is connected with th
5、e hoist drum.Derrick and hoist through the support form the basis of force balance system.Therefore, the wire rope in the rope load derrick load can indeed.Determined as follows:1) The normal work load when the hoist rope (Qk) Standard value: press Mine headframe design GB50385 - 2006 No. 41113 in t
6、he calculation.2) when the wire rope off rope load (Ak) standard values for single-Sheng Ti l, in which a rope for the break Sheng He set out, the other 2 times the normal load; for multi rope, of which the sideSheng He set all the broken rope, the other side of the 0133 times for all the rope off S
7、heng He set.1.2Hoist equipment and basic load transfer betweenGeneral equipment manufacturers to provide information to enhance machine-based, and structure associated with: Equipment and size point of the force, Hole, casing, bolts and steel shear keys and so on.Figure 1. Known by the Figure 1: hoi
8、st by bolts in tension, shear steel shear key to the level of force transmission to the foundation.Hoist the basis of the whole, for the massive foundation.Computational model of a rigid body, based on relatively little between the various parts of deformation, stress level is low, generally may fro
9、m time to calculate an overall strength.70s Red Flag Factory in the 20th century brand compressor assembly-based determination of the surface of steel stress is only 70 140N / cm2 1.The large volume of concrete foundation construction concrete hydration heat in order to prevent the formation of inte
10、rnal and external temperature, and the temperature cracks, generally require basic structural steel surface configuration.But in the elevator equipment and the direct interaction between the concrete foundation of some of the stress concentration significantly, the need for computing and reinforceme
11、nt, the designer often easy to overlook.Mainly for the following two parts: the basis of concrete local office bolt pressure plate, steel embedded in concrete shear key part.The two sites of force transmission to the base hoist the key parts of the design should enhance the machine-based reinforceme
12、nt calculation of local stress and attention.The following detailed discussion of these two parts separately.1.2.1Partial pressure of concreteGeneral bolts provided by the manufacturer, asked the location of civil engineering profession in the corresponding buried steel casing, elevator bolt and pul
13、l through the nut on the local pressure of concrete delivered to the concrete foundation.Concrete local force model similar to the anchor plate with end.Concrete in the base 450 along the failure surface diffusion to form a cone.In order to avoid brittle fracture, can be extended to form a larger co
14、ne bolt failure surface, or around the bolt to configure the reinforced concrete so that the bolt pull in whole or in part by the reinforced passed on.At this point requested by the destruction of tensile reinforcement in the cone base plane and the lower part of the length of not less than the tens
15、ile reinforcement anchorage length.Nut washer in concrete in the local compressive stress is concentrated, in order to prevent local crushing of concrete, this should be part of the reinforced concrete configuration indirect binding, the specific calculation and construction requirements see the des
16、ign of concrete structures GB50010 - 2002 related to the requirements of section.Manufacturers to provide the embedded steel casing and internal bolt gap between the relatively large, refer to the anchor prestressing anchorage ends the construction requirements, should set the basis for concrete and
17、 steel pipe welded steel plate embedded.Steel plate size to no more than the reserved ends bolt hole width is appropriate.Set of steel plate has the advantage of stress can be further spread and reduce the stress level of concrete around the casing.3. American Petroleum Institute, Spec!fication/br W
18、ire Rope. APISpec(fication 9A (Spec 9A), 23rd edn. Washington, DC,1984.4. Djivre, M., Mine ShaJ Ropes: Ontario Destructite Wire Testin,q Program. Ontario Ministry of Labour, Sudbury, Ontario,16 January 1991, p. 5.2 Calculated based on the stability of the hoistHoist by bolts and steel and concrete s
19、hear key base fused to work together.Rope force upgrade process requirements under the direction of the horizontal angle is generally not less than 50 .Improve the level and the vertical component rope are relatively large, and roughly equal.Enhance the pull rope on a diagonal basis of the stability
20、 of negative factors.Therefore, the stability of the need for basic computing.Stability calculation based also includes two aspects: the basis and foundation for overturning the anti-slip.2.1Overturning the basis of calculation2.1.1Overturning stability calculations determine the rotation axis2.2 Ca
21、lculated based on anti-slipThere are two possibilities based on sliding, a surface-based substrate and the substrate to overcome the friction between soil and sliding along the substrate surface.Another level of force to overcome the internal friction of soil to foundation and the bearing layer of s
22、oil with the sliding part.The latter generally difficult to occur because the substrate to allow the general stress of a certain safety factor, which guarantees the basal soil will not produce localized plastic flow to achieve the ultimate balance.Therefore, the only case before the anti-slide stabi
23、lity checking. In the slide there are two favorable factors in the calculation are not taken into account. room with a certain thickness of concrete made on the basis of rigid anti-slide floor effect, in fact, reasonably rigid floor structure has a good foundation to prevent sliding function; backfi
24、ll around the solid basis of a role in stabilizing certain basiceffect.Also based on the foundation soil before the passive earth pressure are generally not considered because of passive earth pressure often associated with the basis of full sliding occurs, and is now commonly used Coulomb theory to
25、 yield the value of passive earth pressure is too large.Therefore, taken together, can reduce the safety factor against sliding, especially in the case of accidental loads. GB50385 - 2006 provides that: derrick-based anti-slip stability factor of 112.Also provides: the foundation and basis for, from
26、 time to broken rope, anti-dropping braking effect of seismic load effect and the combination of checking. Therefore, the basis for the elevator (squat-type shallow foundation) in the off Sheng He set stable under the action of anti-slip coefficient is more appropriate for the 111 112, projects can
27、be economical.3 Other issues needing attention1) Sometimes, in order to increase the basis of weight, often the reducer, motor base and hoist base as a single entity.At this point, there are center-based force together with the projection rope hoist position of greater eccentricity.In the design bas
28、is should be adjusted to some of the ground below, so that the center of the two as close as possible.Weight in order to fully meet the theoretical assumptions.2) As the elevator based on the design layout of the main structure by the surrounding layout and can not re-expand size.Can be taken to inc
29、rease the anti-slide, anchor and uplift piles.To ensure that the foundation Sheng He set off under the stability.3) To improve the capacity of hoist-based sliding the option following structural measures: set rigid floor, foundation backfill around the filling layer compacting ram; for soil under the foundation underside; increase Depth of Foundation; headframe and hoist room based on the actual layout of the situation
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