Tunnel

February 18, 2010 by · Leave a Comment 

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A tunnel is an underground passageway. The definition of what constitutes a tunnel is not universally agreed upon. However, in general tunnels are at least twice as long as they are wide. In addition, they should be completely enclosed on all sides, save for the openings at each end. Some civic planners define a tunnel as 0.1 miles (0.16 km) in length or longer, while anything shorter than this should be called an underpass or a chute. For example, the underpass beneath Yahata Station in Kitakyushu, Japan is only 0.08 miles (0.13 km) long and therefore should not be considered a tunnel.

A tunnel may be for pedestrians or cyclists, for general road traffic, for motor vehicles only, for rail traffic, or for a canal. Some are aqueducts, constructed purely for carrying water — for consumption, for hydroelectric purposes or as sewers — while others carry other services such as telecommunications cables. There are even tunnels designed as wildlife crossings for European badgers and other endangered species. Some secret tunnels have also been made as a method of entrance or escape from an area, such as the Cu Chi Tunnels or the tunnels connecting the Gaza Strip to Egypt. Some tunnels are not for transport at all but are fortifications, for example Mittelwerk and Cheyenne Mountain.

In the United Kingdom a pedestrian tunnel or other underpass beneath a road is called a subway. This term was used in the past in the United States, but now refers to underground rapid transit systems.

The central part of a rapid transit network is usually built in tunnels. To allow non-level crossings, some lines run in deeper tunnels than others. Rail stations with much traffic usually provide pedestrian tunnels from one platform to another, though others use bridges.

It is essential that any tunnel project starts with a comprehensive investigation of ground conditions. The results of the investigation will allow proper choice of machinery and methods for excavation and ground support, and will reduce the risk of encountering unforeseen ground conditions. In the early stages, the horizontal and vertical alignment will be optimized to make use of the best ground and water conditions.

In some cases, conventional desk and site studies will not produce sufficient information to assess, for example, the blocky nature of rocks, the exact location of fault zones, or stand-up times of softer ground. This may be a particular concern in large diameter tunnels. To overcome these problems, a pilot tunnel, or drift, may be driven ahead of the main drive. This smaller diameter tunnel will be easier to support when unexpected conditions occur, and will be incorporated in the final tunnel. Alternatively, horizontal boreholes may sometimes be used ahead of the advancing tunnel face.

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Israel and Egypt Continue to Squeeze Gaza

January 21, 2010 by · Leave a Comment 

By Ann Wright, t r u t h o u t | Op-Ed

Two weeks ago, almost 2,000 internationals came to Egypt and Gaza in a massive show of civil society’s support for the people of Gaza. Nearly 1,400 persons representing 44 countries in the Gaza Freedom March and over 500 persons with the Viva Palestina Convoy let the people of Gaza know of their concern for the tragic consequences of their governments’ support of the Israeli and Egyptian blockade.

Yet, two weeks later, with the apparent approval of governments (United States, European Community and Canada) that support the quarantine, blockade and siege of Gaza, Israel and Egypt have tightened the squeeze to wring the lifeblood out of the people of Gaza.

US Military Team Visits Underground Wall Construction

The US government continues to assist Egypt in building an underground wall to cut off tunnels under the border of Gaza and Egypt. According to Reuters, on January 14, 2010, three US military personnel from the US embassy in Cairo visited Rafah to follow up on the barrier project. According to security sources in Rafah, visits by US military have been taking place monthly.

In a press conference this week in Washington, US State Department spokesman Gordon Duguid said, “What we’d like to see is for Hamas to stop using the border crossings as methods for smuggling in weapons and let’s get the weapons smuggling stopped.” Duguid did not address the use of the tunnels to get life-saving food and materials prohibited by Israel.

In December 2009, three Palestinians were killed after a tunnel collapsed beneath the Egypt-Gaza border. The three were reported missing, and later found by rescue workers.

Deadliest Week Since Last Year’s Israeli Attack

Last week, January 6-12, was the deadliest week for the Gaza Strip in the past year since the January 18, 2009, ceasefire that ended Israel’s “Cast Lead” offensive.

According to the United Nations Office for Coordination of Humanitarian Affairs (OCHA), Israeli air force bombing attacks killed seven Palestinians in Gaza, including three civilians. The attacks came in response to an increase in the number of mortar shells and rockets fired by Palestinian factions from the Gaza Strip into southern Israel that caused no injuries or property damage.

Since the ceasefire a year ago, a total of 84 Palestinians, including at least 27 civilians, and one Israeli (a soldier) have been killed. Another 160 Palestinians and seven Israelis were injured in Gaza and southern Israel.

On January 8, 2010, US aircraft flown by Israeli air force personnel bombed tunnels under the Egypt-Gaza border, killing three Palestinians, including a 15 year-old boy, and wounding another two. Another Palestinian was hurt in a separate airstrike. In two other incidents, on January 6 and 10, Israeli aircraft targeted and killed four Palestinian militants, three of them in one airstrike. Five additional airstrikes, resulting in no casualties, were carried out during the week. Also this week, on four separate occasions, Israeli forces drove tanks into Gaza and conducted land-leveling operations.

Israelis Increase Border Zone Into Gaza

On January 7 this year, the Israeli air force dropped leaflets into areas next to the border fence with Gaza, warning residents to keep a distance of at least 300 meters from the border with Israel and to avoid cooperating with “smugglers” in the tunnels under the Gaza-Egypt border. This doubled the buffer zone along the border from 150 meters to 300 meters, but Israeli forces have opened “warning” fire at farmers as far as 1,000 meters (3,200 feet) from the border.

A parallel ban for Gaza fishermen is applied to sea areas beyond three nautical miles from the coast, though often this distance is less in practice. This week, in nine separate incidents, Israeli naval forces opened “warning” fire at Palestinian fishing boats along Gaza’s coast, forcing them to return to shore.

The Palestinian Centre for Human Rights (PCHR) reported that on January 6 and 9 this year, unknown persons detonated bombs in a pharmacy and two coffee shops in Gaza City; no one was hurt, but property damage was reported.

Two Killed in January in Tunnels and Seven Youths Burned in Tunnel Fire

In January 2010, two Palestinians died in two separate incidents involving the collapse of a tunnel under the Gaza-Egypt border while they were working inside it. At least 70 people have died and 123 others have been injured in the tunnels since the end of the “Cast Lead” Israeli attack on Gaza.

On January 16 this year, seven Palestinians from Gaza were burned in a fire that broke out in one of the tunnels connecting the border towns of Rafah, Gaza and Rafah, Egypt. The seven burned tunnel workers were treated at An-Nasser and Ash-Shifa hospitals in Gaza City.

Digging tunnels and working in them is one of the few jobs available for Palestinian youth in Gaza. Tunnel workers reportedly earn $25 per day, a huge sum in the current Palestinian economy. However, they are subjected to daily bombings by US F-16 aircraft flown by the Israeli Air Force, plus tunnel collapses and fires.

Accidents in the tunnels are frequent. According to the Palestinian human rights organization Al-Mezan, 120 people have been killed working in the tunnel trade in the past three years.

According to OCHA, no commercial gasoline or diesel fuel entered Gaza via Kerem Shalom during last week. Egyptian gasoline and diesel, which is transferred through the tunnels under the Gaza-Egypt border, remains available on the open market, with nearly 100,000 liters of diesel and 100,000 liters of gasoline transferred into Gaza per day.

Israeli Tanks Shell Beit Hanoun

Israeli tanks operating near the northern Gaza border near Beit Hanoun targeted civilian properties with heavy artillery fire on January 15, 2010. Tank shells hit civilian homes on the outskirts of the town, causing material damages but no injuries.

Egypt Builds Anchorage for Border Patrol Boats

Egypt is continuing fortification of its borders with Gaza, this time by sea. According to Reuters, Egypt is constructing a port for patrol boats that will block sea routes into Gaza for merchandise, food and weapons.

The border patrol boats will keep Palestinian fishing boats in Gazan coastal waters. Egypt has said it believes the boats are being used to carry out smuggling operations, though there have never been reports of such incidents. “It is to secure the area. It will be used to direct fishing boats in the area to ensure they do not cross the Israeli sea border and risk getting fired at,” the security sources told Reuters.

As Egypt completes the 14-kilometer underground wall along the Rafah border, Egyptian surveillance of the Mediterranean Sea increases the strangling of Gaza. The tunnels are the only way Gazans can bring goods into the Strip. Israel has maintained a tight blockade of the area, letting in only 36 types of goods for the past three years.

Future Aid Missions Must Go Through Red Crescent

On January 6, hundreds of Palestinians demonstrators, protesting Egypt’s delay in allowing the aid convoy Viva Palestina into Gaza, as well as Egypt’s plans to build the underground steel wall, clashed with Egyptian forces at the Gaza-Egypt border. As a result, an Egyptian soldier was shot dead and 13 Palestinians were injured, including six who suffered gunshot wounds. Eventually, the convoy entered on the same day, carrying food and medical supplies.

However, in response to the clashes, Egypt introduced a new mechanism, through which future aid convoys into Gaza will go through the Egyptian Red Crescent.

No Internationals Allowed Into Gaza

During December, no internationals were allowed into Gaza through the Rafah crossing, until 92 persons from the Gaza Freedom March were allowed in for 48 hours on December 30. During January, only the Viva Palestina convoy personnel were allowed in for 24 hours. Many international persons have letters of invitation from non-governmental organizations to assist in a variety of ways. Only one other international has been allowed into Gaza in January. Egypt has denied the requests for all other internationals. The ability of citizens of the world to assist Gaza when their governments will not is tragically being strangled.

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Tunnels

August 13, 2009 by · Leave a Comment 

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A tunnel is an underground passage that may be used for car or boat traffic, subways, pedestrians, water  or sewage, or power and communication line. Some of the earliest tunnels were the roman aqueducts. They were used to carry clean water into the cities and transport sewage away. Even without electric machinery, the Romans constructed tunnels that lasted until modern time.

The method used to create a tunnel depends on where it is to be constructed and what material will surround it. A tunnel through mountain rock is usually made with a tunnel-boring machine, or mole. This powerful machine is shaped like a large cylinder: it cuts and grinds through rock, leaving behind a passageway. Because rock surrounds the tunnel, extra support isn’t necessary during construction. Explosives were used before the invention of moles, but moles are safer and quieter. They also leave behind a smoother tunnel of the exact shape the engineers want.

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