{"id":14728,"date":"2026-06-23T13:24:01","date_gmt":"2026-06-23T11:24:01","guid":{"rendered":"https:\/\/wp.unil.ch\/geoblog\/?p=14728"},"modified":"2026-06-23T13:26:09","modified_gmt":"2026-06-23T11:26:09","slug":"rock-bridge-mecanics","status":"publish","type":"post","link":"https:\/\/wp.unil.ch\/geoblog\/2026\/06\/rock-bridge-mecanics\/","title":{"rendered":"Rock Bridge Mecanics"},"content":{"rendered":"<figure class=\"wp-block-post-featured-image\"><img loading=\"lazy\" decoding=\"async\" width=\"1036\" height=\"376\" src=\"https:\/\/wp.unil.ch\/geoblog\/files\/2026\/06\/rock-bridge.jpg\" class=\"attachment-post-thumbnail size-post-thumbnail wp-post-image\" alt=\"rock bridge\" style=\"object-fit:cover;\" srcset=\"https:\/\/wp.unil.ch\/geoblog\/files\/2026\/06\/rock-bridge.jpg 1036w, https:\/\/wp.unil.ch\/geoblog\/files\/2026\/06\/rock-bridge-300x109.jpg 300w, https:\/\/wp.unil.ch\/geoblog\/files\/2026\/06\/rock-bridge-1024x372.jpg 1024w, https:\/\/wp.unil.ch\/geoblog\/files\/2026\/06\/rock-bridge-768x279.jpg 768w\" sizes=\"auto, (max-width: 1036px) 100vw, 1036px\" \/><\/figure>\n\n\n<div class=\"wp-block-group has-accent-5-background-color has-background has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\">\n<p class=\"has-accent-5-background-color has-text-color has-background has-link-color wp-elements-aaef9c120becd45e0ce0c9b9dbec9ce0 wp-block-paragraph\" style=\"color:#212121;font-size:clamp(14px, 0.875rem + ((1vw - 3.2px) * 0.49), 19px);\"><em>Th\u00e8se en sciences de la Terre, soutenue le 10 juillet 2026 par Fengchang Bu, rattach\u00e9 \u00e0 l&rsquo;Institut des sciences de la Terre (ISTE) de la FGSE.<\/em><\/p>\n<\/div>\n\n\n\n<p class=\"wp-block-paragraph\">Les discontinuit\u00e9s naturelles telles que les joints et les failles ne sont souvent pas enti\u00e8rement continues. Les segments disjoints, d\u00e9sign\u00e9s selon les disciplines comme des ponts rocheux, des lacunes, des d\u00e9calages ou par des termes analogues, sont ici regroup\u00e9s sous l\u2019appellation g\u00e9n\u00e9rale de ponts rocheux. Une analyse manuelle de 2538 publications parues entre 1962 et 2025 portant sur les pont rocheux r\u00e9v\u00e8le que, malgr\u00e9 l\u2019omnipr\u00e9sence des pont rocheux dans les g\u00e9osciences (glissements de terrain, sismologie, tectonique et g\u00e9otechnique), l\u2019absence d\u2019un cadre m\u00e9canique unifi\u00e9 freine la recherche. Les obstacles majeurs concernent la d\u00e9finition, la m\u00e9trologie, les m\u00e9thodes analytiques, la r\u00e9sistance, les m\u00e9canismes de rupture, la morphologie des fractures, la d\u00e9pendance \u00e0 l\u2019orientation des contraintes, les facteurs d\u00e9terminants et les applications in situ. Cette lacune limite significativement la compr\u00e9hension et la gestion des ph\u00e9nom\u00e8nes g\u00e9ologiques et des ouvrages rocheux, tels que le d\u00e9clenchement de glissements de terrain, la connexion des failles et l\u2019arr\u00eat des s\u00e9ismes.&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Pour \u00e9tablir ce cadre m\u00e9canique, une premi\u00e8re approche fond\u00e9e sur la m\u00e9canique de la rupture a permis de d\u00e9river des solutions analytiques pour l\u2019initiation, la propagation et la coalescence des fissures. L\u2019innovation principale r\u00e9side dans une formulation th\u00e9orique de la propagation des courbes, r\u00e9solvant un probl\u00e8me scientifique vieux de plusieurs d\u00e9cennies. Si les solutions relatives \u00e0 l\u2019initiation et \u00e0 la propagation sont valid\u00e9es exp\u00e9rimentalement, celles li\u00e9es \u00e0 la coalescence restent discutables. La m\u00e9canique de la rupture pr\u00e9sente en effet des limites fondamentales pour d\u00e9crire la rupture des pont rocheux, imposant le recours \u00e0 d&rsquo;autres cadres conceptuels.&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Cons\u00e9quemment, un crit\u00e8re de rupture des pont rocheux a \u00e9t\u00e9 d\u00e9velopp\u00e9, permettant de d\u00e9river leur r\u00e9sistance et leurs modes de rupture. Ce crit\u00e8re transforme le pont rocheux d&rsquo;une entit\u00e9 conceptuelle en un objet analytique, constituant ainsi la base de la m\u00e9canique des pont rocheux. Les r\u00e9sultats sont valid\u00e9s sous diverses conditions : configurations g\u00e9om\u00e9triques (espacement, persistance, inclinaison, angle de pontage), \u00e9tats de contrainte (compression uniaxiale ou triaxiale, traction, cisaillement), conditions in situ (charges de surface, excavation, alt\u00e9ration, saturation, mouvements tectoniques), lithologies (analogues rocheux, gr\u00e8s, calcaire, granite) et types de remplissage. L\u2019int\u00e9gration de la th\u00e9orie du maillon le plus faible et du groupe de renormalisation a produit une solution analytique pr\u00e9disant la rupture, valid\u00e9e par les caract\u00e9ristiques d&rsquo;\u00e9mission acoustique lors d&rsquo;essais sur granite.&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Enfin, ce crit\u00e8re de rupture, coupl\u00e9 \u00e0 des techniques UDEC avanc\u00e9es (\u00e9talonnage par apprentissage automatique et mod\u00e9lisation de l&rsquo;affaiblissement par l&rsquo;eau), a \u00e9t\u00e9 appliqu\u00e9 \u00e0 des cas concrets : mod\u00e8les de versants rocheux, risques d&rsquo;\u00e9boulements Boot Flake en Californie et liaisons de failles the Southern San Andreas Fault\u2013Imperial Fault. Les simulations num\u00e9riques confirment les m\u00e9canismes de connexion actuels et futurs, d\u00e9montrant l&rsquo;efficacit\u00e9 du crit\u00e8re propos\u00e9 pour l&rsquo;int\u00e9gration des pont rocheux dans l&rsquo;ing\u00e9nierie pratique.&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Th\u00e8se en sciences de la Terre<\/p>\n","protected":false},"author":47,"featured_media":14730,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"","_seopress_news_disabled":"","_seopress_video_disabled":"","_seopress_video":[],"_seopress_pro_schemas_manual":[],"_seopress_pro_rich_snippets_disable_all":"","_seopress_pro_rich_snippets_disable":[],"_seopress_pro_schemas":[],"footnotes":"","_links_to":"","_links_to_target":""},"categories":[49465],"tags":[],"class_list":["post-14728","post","type-post","status-publish","format-standard","has-post-thumbnail","category-theses-soutenues"],"_links":{"self":[{"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/posts\/14728","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/users\/47"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/comments?post=14728"}],"version-history":[{"count":3,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/posts\/14728\/revisions"}],"predecessor-version":[{"id":14734,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/posts\/14728\/revisions\/14734"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/media\/14730"}],"wp:attachment":[{"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/media?parent=14728"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/categories?post=14728"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wp.unil.ch\/geoblog\/wp-json\/wp\/v2\/tags?post=14728"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}