Application here is so notorious, the world's scientists have a nickname for this seismic horror：the Mexico City Effect. In the quest of Mexico city earthquake proof, the shifting earth poses its challenge to every construction project, whether above ground or below. Mexico city has the world's third busiest subway system, behind only Moscow and Tokyo, one hundred and seventy six stations, two hundred and seven kilometers of track, more than four million riders a day. But most impressive is that the system's conquest of the rein.
这里有着臭名昭著的应用设施,以致于全世界的科学家有对这个地震的恐怖都有了一个绰号:那就是墨西哥城效果。对于哥城地震的探索证明,地球的姿势偏移挑战着每一项无论是地面或以下的建筑工程。墨西哥城市有着仅次于莫斯科和东京的世界第3繁忙的地铁系统,176家电视台,207公里的铁路,一天400多万人的流量。但最令人印象深刻的是驾驭这个控制系统。
"When we begun to build the subway ,we discovered that the soil was very muddy, so construction was very difficult." The answer was a construction technique called Milan walls, two parallel trenches dug,then filled with concrete and steel rods to form the subway tunnel 's walls, between these walls, the tunnel itself is dug. But engineers run into an obstacle, a law brought in called Archimedes Principle, the same principle allows the submarine to rise, dive or float, the tunnel had to weigh the same as the earth was escalated, weigh less and it would rise, more and it would sink. Instead the tunnel had to float in the soil, to ensure equilibrium, engineers precisely calibrated the weight of the walls to match the displace its soil. Over the open stations, they made up the difference by putting up buildings, no one knew if the Milan walls withstand the earthquake, then came 1995, the quake leveled the worried hospital, the subway station below, not a scratch, the entire system rolled out the seismic waves by floating in the subsoil, in fact the subway was the only way to reach many disaster zones, yet even there is subway tunnel in advance ,the greatest feat of engineering is happening on the surface.
“当我们开始建设地铁时,我们发现,土壤非常泥泞,因此建设是很困难的。”解决办法是被称为米兰墙的建筑技术,两条沟挖墙,填满混凝土和钢棒形成了地铁区间隧道的墙壁,在这些墙壁之间,隧道本身就是挖掘。但是工程师们则遇到一个障碍,一个被称为阿基米德原理的法律，同样的原则允许潜艇上升,潜水或漂浮。由于土地问题，隧道也必须服从这一原理,体重较轻,就会上升,反之则会下沉。相反隧道不得不浮在土壤上,以确保平衡,工程师精确校准墙的重量以替换它的土壤。在开放的地铁站,他们通过建造建筑找到了平衡,没有人知道米兰墙能否承受地震。之后就是1995年的大地震。这次地震夷平了医院,地铁站,不是雁过留痕,而是整个系统随着地震波浮在地基上,事实上地铁是唯一能够到达很多受灾区域的途径,但即使提前有了地铁隧道,最伟大的壮举工程也要建设在表面上。
注：听力文本来源于普特
