1.0Robbinshttps://www.robbinstbm.com/es/rich600338<blockquote class="wp-embedded-content" data-secret="y21vVZWIUQ"><a href="https://www.robbinstbm.com/es/jefferson-barracks-tunnel/">Hard Rock Tunnel Boring at the Jefferson Barracks Tunnel</a></blockquote><iframe sandbox="allow-scripts" security="restricted" src="https://www.robbinstbm.com/es/jefferson-barracks-tunnel/embed/#?secret=y21vVZWIUQ" width="600" height="338" title="“Hard Rock Tunnel Boring at the Jefferson Barracks Tunnel” — Robbins" data-secret="y21vVZWIUQ" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" class="wp-embedded-content"></iframe><script type="text/javascript"> /* <![CDATA[ */ /*! This file is auto-generated */ !function(d,l){"use strict";l.querySelector&&d.addEventListener&&"undefined"!=typeof URL&&(d.wp=d.wp||{},d.wp.receiveEmbedMessage||(d.wp.receiveEmbedMessage=function(e){var t=e.data;if((t||t.secret||t.message||t.value)&&!/[^a-zA-Z0-9]/.test(t.secret)){for(var s,r,n,a=l.querySelectorAll('iframe[data-secret="'+t.secret+'"]'),o=l.querySelectorAll('blockquote[data-secret="'+t.secret+'"]'),c=new RegExp("^https?:$","i"),i=0;i<o.length;i++)o[i].style.display="none";for(i=0;i<a.length;i++)s=a[i],e.source===s.contentWindow&&(s.removeAttribute("style"),"height"===t.message?(1e3<(r=parseInt(t.value,10))?r=1e3:~~r<200&&(r=200),s.height=r):"link"===t.message&&(r=new URL(s.getAttribute("src")),n=new URL(t.value),c.test(n.protocol))&&n.host===r.host&&l.activeElement===s&&(d.top.location.href=t.value))}},d.addEventListener("message",d.wp.receiveEmbedMessage,!1),l.addEventListener("DOMContentLoaded",function(){for(var e,t,s=l.querySelectorAll("iframe.wp-embedded-content"),r=0;r<s.length;r++)(t=(e=s[r]).getAttribute("data-secret"))||(t=Math.random().toString(36).substring(2,12),e.src+="#?secret="+t,e.setAttribute("data-secret",t)),e.contentWindow.postMessage({message:"ready",secret:t},"*")},!1)))}(window,document); //# sourceURL=https://www.robbinstbm.com/wp-includes/js/wp-embed.min.js /* ]]> */ </script> https://www.robbinstbm.com/wp-content/uploads/2022/05/Image-1.jpg22281800The Jefferson Barracks Tunnel runs parallel to the Mississippi River for 5.4 km in limestone, dolomite and shale with potential for karst formations. Read the paper to find out about the challenging conditions encountered by a Robbins TBM, and the new Main Beam machine, launched in 2022 to complete the tunnel.