crossing erratic ground

by:Gewinn     2019-08-17
As the city becomes crowded and busy, it is natural for the public transport system to support underground traffic.
To some extent, Malaysia has deployed light rail and MRT systems in the Basheng Valley;
However, we hardly touch the surface of the subway trip.
San Gabriel-
There are 9 Kajang lines completed in 2017. 5km-
There is a long tunnel for seven subway stations while Sungai Buloh-Serdang-
There are 13 cloth city lines currently under construction.
There are 5 km underground parts of 11 stations.
So far, what have we learned from these tunnel experiences?
One thing is for sure, the geological landscape tunnel in Kuala Lumpur is a walk in the park.
Geological challenges are even experienced in building tunnels here, such as rain water management and road tunnels (SMART)
In the twin tunnels of permb, Larut and Berapit tunnels north of Perak
Track the project, and tunnels for Sungai Buloh
Kajang MRT Line, Metro tunnel engineering contractor-
Gamuda can\'t take things lightly.
\"The primary rule of observation is to treat each tunnel project with caution.
We always respect our position . \"
Dr. Fei, head of geotechnical engineering at Gamuda Ooi Lean.
\"The fact is that the SSP underground route is more difficult to design and build than the SBK route, and less easy.
This is a pretty good one for SBK-
Limited areas of Mount Kenny or KL limestone, there is a difficult transition area in the area of Bukit Bintang.
\"In the SBK series, we were blessed with a relatively good Kenny Hill)
Usually defined by the mutual layers of sandstone and shale)for tunnelling.
The existence of extreme karst (grades 4 and 5)
Targeted ground treatment works at variable density TBMs and specific locations largely address this problem.
\"All in all, when we passed through nine fault zones, we processed two fault zones.
Underground terrain of 5 km . \"
The main challenges faced by SSP tunnels and station builders are 7 inferred fault lines (
Relative to two in the SBK line)
, And various anomalies on the ground that are too small to be detected using the usual soil survey techniques.
\"Geology is much more complicated.
Tunnels are usually deeper, there are more structures and objects underground, the station must be close to the existing high-rise buildings
The value of important buildings . \"
The fault line is an area where rock movements have occurred in the past.
When mild acidic conditions are encountered, these areas tend to undergo weathering and dissolution, thus undermining the continuity of the best conditions for the tunnel.
When the tunnel drilling machine (TBM)
Impact an interface consisting of a large number of mixing zones, which can not be more than a few meters in width, and conditions may change rapidly, thus affecting the working face support pressure of the boring machine.
Since the fault zone is a high-permeability zone, it can also be filled with a large amount of water, thus promoting the movement of groundwater.
All of these factors mean that it is difficult to predict the support pressure and rock strength of the working face of the area where the TBM must pass.
For any tunnel contractor, crossing the fault zone or mixing zone is one of the most dangerous operations in the project.
\"In addition to the fault zone, we have to compete with some folded limestone.
There are many cracks and broken belts in the synchronous and reverse lines themselves, which bring many unexpected challenges to tunnel construction, \"Ooi said.
\"According to the geological profile explained, the two TBMs from Bandar Malaysia North Station to Chan Sow Lin station mostly crossed through limestone.
Although preliminary geological studies have shown that SSP karstic geology is similar to the SBK line, we have experienced more challenging ground conditions in terms of geological trough and mixed working face conditions that are almost impossible to detect.
\"Yes, TBMs encountered a local rockfall on the line of the TBM.
\"Buried geological structures such as faults and folds are difficult to find and require in-depth investigation. Two-
Three dimensional geological profiles may not be able to capture something that is basically three dimensional.
In the process of discrete rock exploration, 3D geological anomalies that may be missed by local troughs, spires or broken rocks.
\"Rocks can also be folded into more than two dimensions, making geological mapping complex,\" Ooi added . \" Who cited a 1993-kilometer KL geological map showing granite intrusion and limestone folding near the rock section.
Tuesday\'s breakthrough is a particularly proud moment for MMC
Gamuda, because it proves that the refurbished machine can successfully complete the tunnel works even after four years of interruption, and the refurbished machine has undergone strict preservation work to keep the machine parts alive. S776 (
(Code for tunnel engineering)
On 2014, after digging the tunnel between Cochrane station and Sungai Buloh-Tun Razak Exchange station, it was retrievedPlus shadow MRT Line.
Ooi said: \"The fact that the machine runs perfectly proves our maintenance system, as well as engineering enhancements, this makes it more effective in dealing with our card drills and other ground conditions that are a bit mixed, adding that by the middle of the year there are a total of 12 TBMs, 8 of which are refurbished here, deploy to work on the SSP line.
S776 successfully crossed 20 m under 14-
Lane Jalan Sungai Besi does not interfere with traffic flow at all, and LRT operated by fast rail continues to operate even under the depth 25 m line of the boring ang LRT
Secondly, the S776 is driven by all Malaysian crew members, which proves the depth and breadth of qualified manpower accumulated by Gamuda over the years, starting with the construction of intelligent tunnels in 2003, the first double in the region
The destination tunnel in Kuala Lumpur is the longest rainwater discharge tunnel in south Kuala Lumpur.
East Asia acts as an underground passage when not used as a drainage facility.
The back of the envelope calculation shows that the average daily advance is 6 m, showing the difficulty of the task to the experienced crew, who are equipped with the state-of-the-art TBM currently on the market.
In response, Ooi said: \"The geology is very complicated and very subtle.
Tunnel construction personnel must understand all of this and make adjustments in case of risk.
This is not a task anyone can come in to undertake.
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