重(かさ)なるto be piled up, to lie on top of one another, to come one after another, to happen over and over, to pile up (e.g. stress), to accumulate, to overlap (each other), to occur at the same time, to happen simultaneously

疲労(ひろう)が重(かさ)なって倒(たお)れる。

To collapse from accumulated fatigue. {to be piled up, to lie on top of one another, to come one after another, to happen over and over, to pile up (e.g. stress), to accumulate, to overlap (each other), to occur at the same time, to happen simultaneously}

彼(かれ)と意見(いけん)が重(かさ)なった。安心(あんしん)した。

My opinion overlapped with his. I feel relieved. {to be piled up, to lie on top of one another, to come one after another, to happen over and over, to pile up (e.g. stress), to accumulate, to overlap (each other), to occur at the same time, to happen simultaneously}

日曜日(にちようび)と祝日(しゅくじつ)が重(かさ)なったので残念(ざんねん)です。

It's unfortunate that Sunday and the holiday overlapped. {to be piled up, to lie on top of one another, to come one after another, to happen over and over, to pile up (e.g. stress), to accumulate, to overlap (each other), to occur at the same time, to happen simultaneously}

身内(みうち)の不幸(ふこう)が重(かさ)なっては食欲(しょくよく)が湧(わ)かなくて当然(とうぜん)だ。

It's natural to lose your appetite when family tragedies come one after another. {to be piled up, to lie on top of one another, to come one after another, to happen over and over, to pile up (e.g. stress), to accumulate, to overlap (each other), to occur at the same time, to happen simultaneously}

次々(つぎつぎ)に偶然(ぐうぜん)が重(かさ)なったのなら、そのように嬉(うれ)しくなるのも当然(とうぜん)です。

If coincidences piled up one after another, it's natural to become happy like that. {to be piled up, to lie on top of one another, to come one after another, to happen over and over, to pile up (e.g. stress), to accumulate, to overlap (each other), to occur at the same time, to happen simultaneously}