{"id":1415,"date":"2023-07-10T19:33:00","date_gmt":"2023-07-10T19:33:00","guid":{"rendered":"https:\/\/ren.roya.org\/?p=1415"},"modified":"2026-02-27T18:01:58","modified_gmt":"2026-02-27T18:01:58","slug":"cerema-une-etude-de-faisabilite-du-retablissement-des-acces-au-tunnel","status":"publish","type":"post","link":"https:\/\/ren.valroya.org\/?p=1415","title":{"rendered":"CEREMA : une \u00e9tude de faisabilit\u00e9 du r\u00e9tablissement des acc\u00e8s au tunnel."},"content":{"rendered":"\n<p><strong>En 2021, la DREAL a command\u00e9 au CEREMA une \u00e9tude de faisabilit\u00e9 du r\u00e9tablissement des acc\u00e8s au tunnel. Nous venons de prendre connaissance de la version italienne de cette \u00e9tude<\/strong>. <strong>Elle est publi\u00e9e sur le site de La Guida.<\/strong> <\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-wp-embed is-provider-la-guida wp-block-embed-la-guida\"><div class=\"wp-block-embed__wrapper\">\n<blockquote class=\"wp-embedded-content\" data-secret=\"EHuOCe7fi7\"><a href=\"https:\/\/laguida.it\/2021\/04\/19\/lo-studio-di-fattibilita-del-ripristino-degli-accessi-al-traforo-stradale-del-colle-di-tenda\/\">Lo studio di fattibilit\u00e0 del ripristino degli accessi al traforo stradale del colle di Tenda<\/a><\/blockquote><iframe loading=\"lazy\" class=\"wp-embedded-content\" sandbox=\"allow-scripts\" security=\"restricted\" style=\"position: absolute; clip: rect(1px, 1px, 1px, 1px);\" title=\"&#8220;Lo studio di fattibilit\u00e0 del ripristino degli accessi al traforo stradale del colle di Tenda&#8221; &#8212; La Guida\" src=\"https:\/\/laguida.it\/2021\/04\/19\/lo-studio-di-fattibilita-del-ripristino-degli-accessi-al-traforo-stradale-del-colle-di-tenda\/embed\/#?secret=8J4RrEl8Br#?secret=EHuOCe7fi7\" data-secret=\"EHuOCe7fi7\" width=\"600\" height=\"338\" frameborder=\"0\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\"><\/iframe>\n<\/div><figcaption><meta charset=\"utf-8\"><a href=\"https:\/\/laguida.it\/wp-content\/uploads\/2021\/04\/1-it_Etude_Faisa_Tende_Memoire_technique_Version-Provisoire-_ita.pdf)\"><meta charset=\"utf-8\">(version PDF : <\/a><a href=\"https:\/\/laguida.it\/wp-content\/uploads\/2021\/04\/1-it_Etude_Faisa_Tende_Memoire_technique_Version-Provisoire-_ita.pdf)\">https:\/\/laguida.it\/wp-content\/uploads\/2021\/04\/1-it_Etude_Faisa_Tende_Memoire_technique_Version-Provisoire-_ita.pdf<\/a>)<\/figcaption><\/figure>\n\n\n\n<p class=\"has-text-color has-medium-font-size\" style=\"color:#feaa00\"><strong>Analyse<\/strong><\/p>\n\n\n\n<p class=\"has-black-color has-text-color has-normal-font-size\"><strong>Le chapitre 2.2.4 \u00ab&nbsp;Destruction des acc\u00e8s au tunnel&nbsp;\u00bb analyse les ph\u00e9nom\u00e8nes observ\u00e9s lors de la temp\u00eate du 2 octobre 2020. A partir du chapitre 2.2.4.4, elle d\u00e9crit avec pr\u00e9cision les effets du comblement du vallon de La C\u00e0 pour les besoins du chantier.<\/strong> <\/p>\n\n\n\n<p><strong>On peut y lire que:<\/strong> <strong>un remblai permettant de faire passer des v\u00e9hicules et d&rsquo;agrandir la plate-forme a progressivement \u00e9t\u00e9 \u00e9difi\u00e9 dans la vallon au niveau des tabliers des deux viaducs. Le 3 octobre 2020, les 25 000 m3 de lave torrentielle parvenus au niveau du remblai l&rsquo;ont submerg\u00e9 et d\u00e9plac\u00e9, ce qui a exerc\u00e9 une pouss\u00e9e lat\u00e9rale sur le tablier du nouveau viaduc provocant sa rupture, elle m\u00eame \u00e0 l&rsquo;origine de la rupture du tablier de l&rsquo;ancien viaduc.<\/strong><\/p>\n\n\n\n<p><strong>Le lit du vallon sous les deux ponts n&rsquo;a pas \u00e9t\u00e9 alt\u00e9r\u00e9, ni combl\u00e9, ce qui confirme que la lave torrentielle a exerc\u00e9 sa pression sur la partie haute des ponts, comme d\u00e9crit dans ces extraits du rapport : \u00ab <em>Un point int\u00e9ressant \u00e0 noter est la rupture du tablier de la structure r\u00e9cente. En effet, celui-ci a tourn\u00e9 autour \u00e0 un axe vertical sans s\u2019effondrer en aval. Ceci t\u00e9moigne d\u2019une force horizontale significative au niveau du pont et d\u2019une cin\u00e9matique de \u00ab\u00a0transport \u00a0\u00bb du tablier pour le faire tourner autour de cet axe. Ce n\u2019est donc pas la destruction des jet\u00e9es qui a conduit \u00e0 la destruction du viaduc, mais un effort lat\u00e9ral. La figure 41 montre la forme de destruction cette structure. \u00bb<\/em><\/strong><\/p>\n\n\n\n<p><strong><em>\u00abUn autre point important \u00e0 noter est que La C\u00e0 n\u2019a pas creus\u00e9 son lit au niveau des viaducs ; ceci sugg\u00e8re l\u2019absence d\u2019\u00e9rosion dans les fondations. Dans ce secteur La C\u00e0 a d\u00e9pos\u00e9 beaucoup de mat\u00e9riaux, mais son lit majeur est rest\u00e9 au m\u00eame niveau altim\u00e9trique. En effet, les trois seuils pr\u00e9existants n\u2019ont pas \u00e9t\u00e9 d\u00e9truits lors de l\u2019\u00e9v\u00e9nement d\u2019octobre&nbsp;2020, ni les murs plac\u00e9s sous les \u00e9paules des deux viaducs. Les illustrations suivantes montrent ces \u00e9l\u00e9ments. Ceci est visible dans la figure 42 et figure 43<\/em>.\u00bb<\/strong><\/p>\n\n\n\n<p>\u00ab<strong><em>Il s\u2019agit donc en effet de deux ph\u00e9nom\u00e8nes distincts qui ont conduit \u00e0 la destruction des deux viaducs; d\u2019abord un glissement de terrain suivi d\u2019une lave torrentielle puis la rupture par glissement de terrain et \u00e9rosion de la plate-forme intub\u00e9e.<\/em>\u00bb<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel3_4octobre_-1-scaled.jpg\"><img decoding=\"async\" src=\"https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel3_4octobre_-1-1024x318.jpg\" alt=\"\" class=\"wp-image-1419\"\/><\/a><\/figure>\n\n\n\n<p class=\"has-text-color has-medium-font-size\" style=\"color:#feaa00\"><strong>Conclusion<\/strong><\/p>\n\n\n\n<p><strong>Il appara\u00eet clairement que les prescriptions \u00e9tablies au titre de la loi sur l&rsquo;eau dans la DUP de 2007 n&rsquo;ont pas \u00e9t\u00e9 respect\u00e9es, ni pour la construction du nouveau viaduc, comme nous l&rsquo;avions d\u00e9nonc\u00e9 en 2017, ni pour les \u00e9largissements successifs de la plate-forme du chantier. Et que cela a eu pour cons\u00e9quences la destruction successive du viaduc neuf et de l&rsquo;ancien.<\/strong><\/p>\n\n\n\n<p class=\"has-text-color has-medium-font-size\" style=\"color:#feaa00\"><strong>Traduction et images <\/strong><\/p>\n\n\n<a href=\"https:\/\/ren.valroya.org\/wp-content\/uploads\/LG_Viaduc2023Annexes.pdf\" class=\"pdfemb-viewer\" style=\"\" data-width=\"max\" data-height=\"max\" data-toolbar=\"bottom\" data-toolbar-fixed=\"off\">LG_Viaduc2023Annexes<\/a>\n<p class=\"wp-block-pdfemb-pdf-embedder-viewer\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>En 2021, la DREAL a command\u00e9 au CEREMA une \u00e9tude de faisabilit\u00e9 du r\u00e9tablissement des acc\u00e8s au tunnel. Nous venons de prendre connaissance de la version italienne de cette \u00e9tude. Elle est publi\u00e9e sur le site de La Guida. Analyse Le chapitre 2.2.4 \u00ab&nbsp;Destruction des acc\u00e8s au tunnel&nbsp;\u00bb analyse les ph\u00e9nom\u00e8nes observ\u00e9s lors de la [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":1997,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","footnotes":""},"categories":[18,7],"tags":[],"class_list":["post-1415","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-actualite-tunnel","category-transition"],"author_data":{"name":"adminren","url":"https:\/\/ren.valroya.org\/?author=3"},"excerpt_data":"En 2021, la DREAL a command\u00e9 au CEREMA une \u00e9tude de faisabilit\u00e9 du r\u00e9tablissement des...","categories_data":{"18":{"term_id":18,"name":"Actualit\u00e9 Tunnel","slug":"actualite-tunnel","term_group":0,"term_taxonomy_id":18,"taxonomy":"category","description":"","parent":0,"count":12,"filter":"raw","cat_ID":18,"category_count":12,"category_description":"","cat_name":"Actualit\u00e9 Tunnel","category_nicename":"actualite-tunnel","category_parent":0},"7":{"term_id":7,"name":"Transition","slug":"transition","term_group":0,"term_taxonomy_id":7,"taxonomy":"category","description":"","parent":0,"count":16,"filter":"raw","cat_ID":7,"category_count":16,"category_description":"","cat_name":"Transition","category_nicename":"transition","category_parent":0}},"featured_image_src":"https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel4octobre__.jpg","date_formated":"July 10, 2023","uagb_featured_image_src":{"full":["https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel4octobre__.jpg",365,274,false],"thumbnail":["https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel4octobre__-150x150.jpg",150,150,true],"medium":["https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel4octobre__-300x225.jpg",300,225,true],"medium_large":["https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel4octobre__.jpg",365,274,false],"large":["https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel4octobre__.jpg",365,274,false],"1536x1536":["https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel4octobre__.jpg",365,274,false],"2048x2048":["https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel4octobre__.jpg",365,274,false],"blogus-slider-full":["https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel4octobre__.jpg",365,274,false],"blogus-featured":["https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel4octobre__.jpg",365,274,false],"blogus-medium":["https:\/\/ren.valroya.org\/wp-content\/uploads\/tunnel4octobre__.jpg",365,274,false]},"uagb_author_info":{"display_name":"adminren","author_link":"https:\/\/ren.valroya.org\/?author=3"},"uagb_comment_info":0,"uagb_excerpt":"En 2021, la DREAL a command\u00e9 au CEREMA une \u00e9tude de faisabilit\u00e9 du r\u00e9tablissement des acc\u00e8s au tunnel. Nous venons de prendre connaissance de la version italienne de cette \u00e9tude. Elle est publi\u00e9e sur le site de La Guida. Analyse Le chapitre 2.2.4 \u00ab&nbsp;Destruction des acc\u00e8s au tunnel&nbsp;\u00bb analyse les ph\u00e9nom\u00e8nes observ\u00e9s lors de la\u2026","_links":{"self":[{"href":"https:\/\/ren.valroya.org\/index.php?rest_route=\/wp\/v2\/posts\/1415","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ren.valroya.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ren.valroya.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ren.valroya.org\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/ren.valroya.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1415"}],"version-history":[{"count":4,"href":"https:\/\/ren.valroya.org\/index.php?rest_route=\/wp\/v2\/posts\/1415\/revisions"}],"predecessor-version":[{"id":1424,"href":"https:\/\/ren.valroya.org\/index.php?rest_route=\/wp\/v2\/posts\/1415\/revisions\/1424"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ren.valroya.org\/index.php?rest_route=\/wp\/v2\/media\/1997"}],"wp:attachment":[{"href":"https:\/\/ren.valroya.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1415"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ren.valroya.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1415"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ren.valroya.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1415"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}