JPH0376361B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for improving a track bed, and is used to improve a soft road bed part of a railway track in commercial use during a short suspension of operation, such as at night. (Prior art) Generally, on railway tracks, vibration loads from vehicles are continuously applied, so fine powder from subgrade soil and crushed stone mixes with rainwater, turns into mud, and blows up onto sleepers.
Alternatively, it often occurs that crushed stone from the roadbed sinks into the roadbed. When the mud-spraying phenomenon occurs, the track gradually weakens and loses its appropriate elasticity, and the track also develops height differences and bends, necessitating repairs such as so-called trackbed replacement. Therefore, on railways that are in commercial use, all of the track bed replacement and track base repair work must be completed within a short period of time at night, which inevitably requires manual work using conventional track engineering. Instead, mechanized track maintenance will become necessary. In reality, track maintenance machines such as multiple tampers, which are equivalent to track maintenance robots, are used to improve work efficiency and cope with manpower shortages. By the way, mechanized track maintenance using track maintenance robots is superior in terms of work efficiency, etc., but since the work is carried out according to a predetermined program, it is difficult to perform detailed track maintenance that adapts to the uniqueness of the so-called site. The problem is that it cannot work. For example, the above-mentioned mud blowing phenomenon on the track occurs locally at railroad crossings and part of the embanked track, but in the above-mentioned mechanized track maintenance, special track maintenance work is carried out only on weak parts of the roadbed. It is impossible to increase the frequency of the roadbed, or to perform so-called "additional pounding and compaction" for only weak sections of the roadbed, and it is impossible to do so. Become. As a result, even if track maintenance work is completed, as described above, the soft areas of the roadbed are not thoroughly pounded and hardened, so mud will continue to erupt from the same areas. On the other hand, in order to strengthen the weak spots in the track base as described above, methods have been adopted such as replacing the subgrade soil or forming a concrete layer below the crushed stone of the roadbed. However, replacing the subgrade soil requires a long work time, and the cost of reinforcing the subgrade is high. Furthermore, the method of forming a concrete layer has been proven to cause mud to blow from the cracks in the concrete plate, making repair difficult. On the other hand, in recent years, when constructing a new railway, a method has been developed and put into use for reinforcing the track base using granulated slag. That is, as shown in FIG. 2, after forming a Nishiya fault (if the subgrade is clayey soil) 2 on the subgrade soil 1, and further laying particle size-adjusted crushed stone 3 and particle size-adjusted slag 4 on top of it, An asphalt emulsion layer 5 is laid on the outer surface of the slag layer 4. The asphalt emulsion layer 5 prevents water evaporation in the slag layer 4, and by compacting the slag layer 4 with a moisture content of around 10%, the so-called hydraulic property of the slag causes it to coagulate and harden. After several months, the compressive strength reaches 30 to 60 Kg/cm ² , and the curing continues for a long time, and finally a compressive strength of 100 to 120 Kg/cm ² is achieved. In addition, the coagulated and hardened slag layer 4 prevents mud from blowing up from the subgrade soil, prevents subsidence of crushed stones from the subgrade, reduces subgrade displacement by evenly distributing the load, and improves the subgrade condition by reducing rainwater infiltration. etc.,
It has many positive effects on the trajectory. However, it takes a considerable period of time for the particle size-adjusting slag layer 4 to completely coagulate and solidify, and it is also necessary to sufficiently compact the slag in an appropriate moisture content state.
10 times of compaction and macadam roller 10t~1
Requires 3 to 5 rolling presses of 2t. Therefore, there is no problem when constructing a new track base, but in order to use particle size-adjusted slag to improve the track base of railways in operation, improvements must be made to the compaction method of the slag, and solidification is required. It is necessary to reduce the compaction time required. In other words, the conventional compaction method of compacting granule-adjusted slag many times with tire rollers or macadam rollers is absolutely insufficient in working time, and economical reinforcement of the roadbed cannot be achieved. (Problems to be Solved) The present invention solves the above-mentioned problems when improving the track base of railways in commercial operation using grain-adjusted slag, namely, it takes time to pound and harden the laid slag layer. This is an attempt to solve the problem that it is difficult to apply to roadbed improvement work that needs to be completed within a short period of time. That is, the present invention provides sufficient moisture in advance to the slag to be laid on the subgrade soil, and when the slag is compacted by the impact force of a rammer or the like, the moisture contained in the slag is released from the inside of the slag, and the internally released moisture is Therefore, by achieving rapid coagulation within a short period of time and by hardening the compacted slag over a long period of time using the weight of moving vehicles, the time required for roadbed improvement work can be significantly shortened. The present invention provides a method for improving trackbeds in service that makes it possible to use slag. (Means for Solving the Problems) In order to achieve the above object, the inventors of the present invention repeatedly conducted studies and hardening tests on the hardening mechanism of particle size-adjusted slag due to hydration reaction, and learned the following phenomenon from the results. In the conventional method of laying slag particles and rolling them with tire rollers over time while adding water, condensation and hardening due to hydration reaction gradually progresses inward from the outer surface of the slag particles. , requiring a relatively long time for curing. On the other hand, if the slag is sufficiently moistened with water before being laid, and then it is compacted using an impact force such as a rammer, the impact will cause the moisture contained inside the slag particles to be absorbed. is released,
The coagulation effect due to the so-called hydration reaction proceeds from inside the slag particle layer and condenses within a very short time, and a compressive strength of approximately 70% of the final hardening compressive strength is obtained within a few hours after compaction. By continuously applying water and a certain compression/vibration load to the slag layer that has been compacted by the impact force of a rammer and condensed within a short time, the hydraulic properties of the particle size-adjusted slag are sufficiently improved. After 3 to 4 months, a compressive strength equivalent to that obtained when the entire layer of slag is evenly compacted using rollers or the like should be obtained. The above-mentioned phenomenon was caused by the fact that when slag was first used for road paving, etc., even if sufficient initial compaction could not be achieved due to lack of mechanical power, the weight of passing vehicles would gradually compact the slag. This is consistent with the fact that a strong slag pavement was obtained after ~3 months. The present invention involves removing the subgrade soil from the soft parts of the track base of a railway in operation to a certain depth, and then laying granule-adjusted slag that has been sufficiently watered in advance. The slag is compacted by the impact force of a rammer, etc., and the water is pushed out from the slag by the compaction to condense the granule-adjusted slag within a short period of time.A wire mesh is laid above the compacted slag, and a wire mesh is placed on top of the slag. By laying crushed stone on the roadbed with a particle size larger than the mesh of the mesh, and using the weight of the traveling vehicle to pressurize and compress the particle size-adjusted slag through the crushed stone layer on the roadbed separated by the wire mesh, the slag is solidified within a short time. The basic structure of the invention is to coagulate and harden the slag layer. (Function) The grain size-adjusted slag, which has been hydrated in advance to a saturated state, is subjected to an impact compression force using a rammer, etc., so that the moisture content inside is pushed out, and the so-called hydration reaction rapidly progresses. Hydraulic properties appear. As a result, the laid slag is solidified within a short time, and a compressive strength of about 70% of the final compressive strength is obtained. On the other hand, when a vehicle passes through the road, the weight of the vehicle is transferred to the slag layer through the road bed crushed stone layer wrapped in a wire mesh, and the slag layer is compressed over a long period of time. In other words, the roadbed crushed stone layer wrapped in wire mesh is
The wire mesh completely separates it from the slag layer, and the two vibrate upward and downward as separate bodies. As a result, the slag layer is compressed very efficiently and evenly by the weight of the vehicle, thereby promoting hardening and ultimately forming a strong slag roadbed. (Example) Fig. 1 is a longitudinal cross-sectional view of a railway track in which the present invention was implemented, and in the figure, 6 is a roadbed, 7 is a particle size-adjusted slag, 8 is crushed rock, 9 is a wire mesh, and 10 is a PC sleeper. ,
11 is a rail. Referring to FIG. 1, when improving a soft roadbed part (for example, a railroad crossing part, etc.) of a railway track according to the present invention, first, the upper layer of crushed stones 8 of the soft roadbed part is removed, and the sleepers 10 between them are removed. Loosen it and push it to one side, or temporarily remove it. Next, sleeper 1
Approximately 200 pieces of crushed stone 8 and the roadbed directly below it.
Exclude plowing to a depth of ~250mm. When the plowing of the roadbed is completed, 20 to 25 cm thick granulated slag 7, which has been soaked in water in advance and sufficiently hydrated, is laid on the plowed part of the roadbed, and the surface layer is pounded with a rammer etc. Pulse 3 to 5 times to harden.
In addition, as a rammer, the weight of the oil automatic lubrication type is
The best one is one that weighs 80 to 100 kg and has a vibration frequency of 550 to 600 times/minute. Further, as the particle size adjusting slag 7, it is desirable to use slag having a particle size distribution as shown in the table below.

[Table] Furthermore, since the granulated slag is porous and consolidated by pounding and hardening with a rammer, the amount of slag should be approximately 1.1 to 1.3 times the volume of the plowed roadbed. For example, if the slag is soaked in water several hours before the start of work, water is added sufficiently, the slag is laid (the thickness of the slag layer 7 is 20 cm), and the slag is rammed about 4 times with the rammer, The slag layer is pounded and solidified to a thickness of about 14 cm, and after 2 hours from being laid, it solidifies to the extent that it exhibits a compressive strength of 20 to 30 kg/cm ² . When the leveling of the slag 7 and the pounding and hardening of the surface layer of the slag with a rammer or the like are completed, a wire mesh 9 having a mesh smaller than the grain size of the roadbed crushed stones 8 is placed above the slag layer 7.
(In this example, since the grain size of the road bed crushed stones 8 is 25 to 40 mm, a wire mesh with a mesh size of 25 mm or less) is laid, and on top of that, the road bed crushed stones 8 are laid with a thickness of about 250 mm, and this is covered with the wire mesh 9. Be in a state of encirclement. When the leveling of the laid road bed crushed stones 8 is completed, the sleepers 10 are finally pulled back to a predetermined position and are tightened and fixed to the rails 11, and then additional road bed crushed stones 8 are laid and the road bed is pounded and compacted. By sequentially repeating the above-mentioned steps in units of 7 to 8 m long sections, a predetermined length of the track base is repaired. In addition, when improving the roadbed using the method of the present invention, a power shovel, etc., should be carried to the soft roadbed using a truck for roadbed changing equipment (Utility Application No. 17271, 1983) developed earlier by the inventor of the present application. It is most ideal to use a self-propelled track bed exchanger (Japanese Patent Application No. 125415/1982). Immediately after the slag has been laid for the purpose of improving the roadbed, it has not sufficiently and completely solidified and hardened due to the so-called hydration reaction, but as vehicles pass through it, it becomes wrapped in the wire mesh 9. The lower slag layer 7 is compressed and rolled evenly over a long period of time through the crushed stone 8 in the roadbed, and is sequentially solidified and hardened while being subjected to the compressive force. That is, as a vehicle runs on the rails 11, the weight of the vehicle is transferred to the slag layer 7 via the road bed crushed stone layer 8 wrapped in the wire mesh 9, and the road bed crushed stone layer 8 and the slag layer 7 are separated by the wire mesh. 9, they move up and down not as one body but as separate bodies, and the slag layer 7 is compressed and compacted by the up and down vibration of the crushed rock layer 8. On the other hand, the amount of water necessary for the hydration reaction is added in advance to the slag layer 7 when the slag is laid, and the surface layer of the slag layer 7 is pounded and hardened when the slag is laid, so no moisture is absorbed. evaporation is prevented. or,
The slag layer 7 can be constructed as needed by rainwater or water supply if necessary.
As water is added inside, the slag layer 7 hardens from the inside while being subjected to compaction pressure due to the weight of the vehicle over time, and after 2 to 3 months, the slag layer 7 hardens to 60 to 80%.
An extremely strong slag roadbed with a compressive strength of about Kg/cm ² is formed. As the slag layer 7 solidifies and hardens, the slag layer 7 may be compressed by about 2 to 3 mm, causing slight subsidence of the track. However, the subsidence of the track is usually about 1 to 2 mm, and there is no need to repair the subsidence of the track by adding crushed stone to the track bed and compacting it. (Effects of the Invention) In the present invention, the slag is soaked in water in advance so that it contains sufficient moisture, and the entire layer of the slag layer 7 that has been laid is not compacted at once, but when the slag is laid, a rammer etc. The structure is such that the slag layer is compacted and hardened by the impact force of 100 ml to cause early solidification, and then the weight of the vehicle is used to compress and harden the slag layer over a long period of time. Therefore, the working time required to compact the slag layer 7 is significantly shorter than before, and the internal water is pushed out by the compaction due to the impact force of the rammer, and the coagulation reaction of the slag is significantly accelerated. Since the desired compressive strength can be obtained, track base improvement work using slag can be carried out even on commercial lines. Further, in the present invention, since the wire mesh 9 is used to enclose the roadbed crushed stone 8, the wire mesh 9 acts as a separator, and the slag layer 7 and the roadbed crushed stone layer 8 cannot move up and down as one. They each become separate bodies and vibrate up and down. As a result, the crushed stone layer 8 wrapped in a wire mesh performs the same function as a rolling indenter, and the slag layer 7 is efficiently and evenly compressed over a long period of time, forming a stronger slag slab. . Furthermore, since the coagulated and hardened slag layer 7 has appropriate flexibility, cracks will not occur due to vehicle vibrations, and even if a crack occurs, water will be supplied. As a result, the hydration reaction is restarted and the crack is repaired, so there is an advantage that the mud blowing phenomenon will never occur again. Additionally, slag slabs have the property of being permeable to moisture but not mud. Therefore, the viscosity of the roadbed becomes mud and there is no possibility of it being ejected onto the track, and even if the crushed rock of the roadbed is pulverized, it will not turn into mud, and there will be no phenomenon of so-called mud blowing onto the roadbed. As described above, the present invention has extremely high practical utility in improving the track base of railways in operation within a short period of time, such as during a late-night suspension of operation.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a railway track in which the present invention is implemented. Figure 2 is a cross-sectional view of a new track that uses conventional mine slag. 6...Roadbed, 7...Grain size adjustment slag layer, 8...Road bed crushed stone layer, 9...Wire mesh, 10...Sleepers, 11...Rail.

Claims (1)

[Claims] 1. In railway roadbeds in operation, the subgrade soil in the soft parts of the roadbed is removed to a certain depth, and then granulated slag that has been sufficiently watered in advance is laid down and the soil is removed using a rammer, etc. The slag is compacted by impact force, and the water is pushed out from the slag by the compaction to condense the granule-adjusted slag within a short period of time.A wire mesh is laid above the compacted slag, and the mesh of the wire mesh is placed on top of the slag. The slag is coagulated in a short time by laying road bed crushed stones having a large particle size and pressurizing and compressing the particle size-adjusted slag through the road bed crushed stone layer separated by the wire mesh using the weight of a running vehicle. A method for improving a track base course, characterized by solidifying and hardening the layer over a long period of time.